--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sql/SQLite/select.c Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,4292 @@
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle SELECT statements in SQLite.
+**
+** $Id: select.c,v 1.463 2008/08/04 03:51:24 danielk1977 Exp $
+*/
+#include "sqliteInt.h"
+
+
+/*
+** Delete all the content of a Select structure but do not deallocate
+** the select structure itself.
+*/
+static void clearSelect(sqlite3 *db, Select *p){
+ sqlite3ExprListDelete(db, p->pEList);
+ sqlite3SrcListDelete(db, p->pSrc);
+ sqlite3ExprDelete(db, p->pWhere);
+ sqlite3ExprListDelete(db, p->pGroupBy);
+ sqlite3ExprDelete(db, p->pHaving);
+ sqlite3ExprListDelete(db, p->pOrderBy);
+ sqlite3SelectDelete(db, p->pPrior);
+ sqlite3ExprDelete(db, p->pLimit);
+ sqlite3ExprDelete(db, p->pOffset);
+}
+
+/*
+** Initialize a SelectDest structure.
+*/
+void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
+ pDest->eDest = eDest;
+ pDest->iParm = iParm;
+ pDest->affinity = 0;
+ pDest->iMem = 0;
+ pDest->nMem = 0;
+}
+
+
+/*
+** Allocate a new Select structure and return a pointer to that
+** structure.
+*/
+Select *sqlite3SelectNew(
+ Parse *pParse, /* Parsing context */
+ ExprList *pEList, /* which columns to include in the result */
+ SrcList *pSrc, /* the FROM clause -- which tables to scan */
+ Expr *pWhere, /* the WHERE clause */
+ ExprList *pGroupBy, /* the GROUP BY clause */
+ Expr *pHaving, /* the HAVING clause */
+ ExprList *pOrderBy, /* the ORDER BY clause */
+ int isDistinct, /* true if the DISTINCT keyword is present */
+ Expr *pLimit, /* LIMIT value. NULL means not used */
+ Expr *pOffset /* OFFSET value. NULL means no offset */
+){
+ Select *pNew;
+ Select standin;
+ sqlite3 *db = pParse->db;
+ pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
+ assert( !pOffset || pLimit ); /* Can't have OFFSET without LIMIT. */
+ if( pNew==0 ){
+ pNew = &standin;
+ memset(pNew, 0, sizeof(*pNew));
+ }
+ if( pEList==0 ){
+ pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0,0,0), 0);
+ }
+ pNew->pEList = pEList;
+ pNew->pSrc = pSrc;
+ pNew->pWhere = pWhere;
+ pNew->pGroupBy = pGroupBy;
+ pNew->pHaving = pHaving;
+ pNew->pOrderBy = pOrderBy;
+ pNew->isDistinct = isDistinct;
+ pNew->op = TK_SELECT;
+ assert( pOffset==0 || pLimit!=0 );
+ pNew->pLimit = pLimit;
+ pNew->pOffset = pOffset;
+ pNew->addrOpenEphm[0] = -1;
+ pNew->addrOpenEphm[1] = -1;
+ pNew->addrOpenEphm[2] = -1;
+ if( pNew==&standin) {
+ clearSelect(db, pNew);
+ pNew = 0;
+ }
+ return pNew;
+}
+
+/*
+** Delete the given Select structure and all of its substructures.
+*/
+void sqlite3SelectDelete(sqlite3 *db, Select *p){
+ if( p ){
+ clearSelect(db, p);
+ sqlite3DbFree(db, p);
+ }
+}
+
+/*
+** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
+** type of join. Return an integer constant that expresses that type
+** in terms of the following bit values:
+**
+** JT_INNER
+** JT_CROSS
+** JT_OUTER
+** JT_NATURAL
+** JT_LEFT
+** JT_RIGHT
+**
+** A full outer join is the combination of JT_LEFT and JT_RIGHT.
+**
+** If an illegal or unsupported join type is seen, then still return
+** a join type, but put an error in the pParse structure.
+*/
+int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
+ int jointype = 0;
+ Token *apAll[3];
+ Token *p;
+ static const struct {
+ const char zKeyword[8];
+ u8 nChar;
+ u8 code;
+ } keywords[] = {
+ { "natural", 7, JT_NATURAL },
+ { "left", 4, JT_LEFT|JT_OUTER },
+ { "right", 5, JT_RIGHT|JT_OUTER },
+ { "full", 4, JT_LEFT|JT_RIGHT|JT_OUTER },
+ { "outer", 5, JT_OUTER },
+ { "inner", 5, JT_INNER },
+ { "cross", 5, JT_INNER|JT_CROSS },
+ };
+ int i, j;
+ apAll[0] = pA;
+ apAll[1] = pB;
+ apAll[2] = pC;
+ for(i=0; i<3 && apAll[i]; i++){
+ p = apAll[i];
+ for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
+ if( p->n==keywords[j].nChar
+ && sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
+ jointype |= keywords[j].code;
+ break;
+ }
+ }
+ if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
+ jointype |= JT_ERROR;
+ break;
+ }
+ }
+ if(
+ (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
+ (jointype & JT_ERROR)!=0
+ ){
+ const char *zSp = " ";
+ assert( pB!=0 );
+ if( pC==0 ){ zSp++; }
+ sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
+ "%T %T%s%T", pA, pB, zSp, pC);
+ jointype = JT_INNER;
+ }else if( jointype & JT_RIGHT ){
+ sqlite3ErrorMsg(pParse,
+ "RIGHT and FULL OUTER JOINs are not currently supported");
+ jointype = JT_INNER;
+ }
+ return jointype;
+}
+
+/*
+** Return the index of a column in a table. Return -1 if the column
+** is not contained in the table.
+*/
+static int columnIndex(Table *pTab, const char *zCol){
+ int i;
+ for(i=0; i<pTab->nCol; i++){
+ if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
+ }
+ return -1;
+}
+
+/*
+** Set the value of a token to a '\000'-terminated string.
+*/
+static void setToken(Token *p, const char *z){
+ p->z = (u8*)z;
+ p->n = z ? strlen(z) : 0;
+ p->dyn = 0;
+}
+
+/*
+** Set the token to the double-quoted and escaped version of the string pointed
+** to by z. For example;
+**
+** {a"bc} -> {"a""bc"}
+*/
+static void setQuotedToken(Parse *pParse, Token *p, const char *z){
+
+ /* Check if the string contains any " characters. If it does, then
+ ** this function will malloc space to create a quoted version of
+ ** the string in. Otherwise, save a call to sqlite3MPrintf() by
+ ** just copying the pointer to the string.
+ */
+ const char *z2 = z;
+ while( *z2 ){
+ if( *z2=='"' ) break;
+ z2++;
+ }
+
+ if( *z2 ){
+ /* String contains " characters - copy and quote the string. */
+ p->z = (u8 *)sqlite3MPrintf(pParse->db, "\"%w\"", z);
+ if( p->z ){
+ p->n = strlen((char *)p->z);
+ p->dyn = 1;
+ }
+ }else{
+ /* String contains no " characters - copy the pointer. */
+ p->z = (u8*)z;
+ p->n = (z2 - z);
+ p->dyn = 0;
+ }
+}
+
+/*
+** Create an expression node for an identifier with the name of zName
+*/
+Expr *sqlite3CreateIdExpr(Parse *pParse, const char *zName){
+ Token dummy;
+ setToken(&dummy, zName);
+ return sqlite3PExpr(pParse, TK_ID, 0, 0, &dummy);
+}
+
+/*
+** Add a term to the WHERE expression in *ppExpr that requires the
+** zCol column to be equal in the two tables pTab1 and pTab2.
+*/
+static void addWhereTerm(
+ Parse *pParse, /* Parsing context */
+ const char *zCol, /* Name of the column */
+ const Table *pTab1, /* First table */
+ const char *zAlias1, /* Alias for first table. May be NULL */
+ const Table *pTab2, /* Second table */
+ const char *zAlias2, /* Alias for second table. May be NULL */
+ int iRightJoinTable, /* VDBE cursor for the right table */
+ Expr **ppExpr, /* Add the equality term to this expression */
+ int isOuterJoin /* True if dealing with an OUTER join */
+){
+ Expr *pE1a, *pE1b, *pE1c;
+ Expr *pE2a, *pE2b, *pE2c;
+ Expr *pE;
+
+ pE1a = sqlite3CreateIdExpr(pParse, zCol);
+ pE2a = sqlite3CreateIdExpr(pParse, zCol);
+ if( zAlias1==0 ){
+ zAlias1 = pTab1->zName;
+ }
+ pE1b = sqlite3CreateIdExpr(pParse, zAlias1);
+ if( zAlias2==0 ){
+ zAlias2 = pTab2->zName;
+ }
+ pE2b = sqlite3CreateIdExpr(pParse, zAlias2);
+ pE1c = sqlite3PExpr(pParse, TK_DOT, pE1b, pE1a, 0);
+ pE2c = sqlite3PExpr(pParse, TK_DOT, pE2b, pE2a, 0);
+ pE = sqlite3PExpr(pParse, TK_EQ, pE1c, pE2c, 0);
+ if( pE && isOuterJoin ){
+ ExprSetProperty(pE, EP_FromJoin);
+ pE->iRightJoinTable = iRightJoinTable;
+ }
+ *ppExpr = sqlite3ExprAnd(pParse->db,*ppExpr, pE);
+}
+
+/*
+** Set the EP_FromJoin property on all terms of the given expression.
+** And set the Expr.iRightJoinTable to iTable for every term in the
+** expression.
+**
+** The EP_FromJoin property is used on terms of an expression to tell
+** the LEFT OUTER JOIN processing logic that this term is part of the
+** join restriction specified in the ON or USING clause and not a part
+** of the more general WHERE clause. These terms are moved over to the
+** WHERE clause during join processing but we need to remember that they
+** originated in the ON or USING clause.
+**
+** The Expr.iRightJoinTable tells the WHERE clause processing that the
+** expression depends on table iRightJoinTable even if that table is not
+** explicitly mentioned in the expression. That information is needed
+** for cases like this:
+**
+** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
+**
+** The where clause needs to defer the handling of the t1.x=5
+** term until after the t2 loop of the join. In that way, a
+** NULL t2 row will be inserted whenever t1.x!=5. If we do not
+** defer the handling of t1.x=5, it will be processed immediately
+** after the t1 loop and rows with t1.x!=5 will never appear in
+** the output, which is incorrect.
+*/
+static void setJoinExpr(Expr *p, int iTable){
+ while( p ){
+ ExprSetProperty(p, EP_FromJoin);
+ p->iRightJoinTable = iTable;
+ setJoinExpr(p->pLeft, iTable);
+ p = p->pRight;
+ }
+}
+
+/*
+** This routine processes the join information for a SELECT statement.
+** ON and USING clauses are converted into extra terms of the WHERE clause.
+** NATURAL joins also create extra WHERE clause terms.
+**
+** The terms of a FROM clause are contained in the Select.pSrc structure.
+** The left most table is the first entry in Select.pSrc. The right-most
+** table is the last entry. The join operator is held in the entry to
+** the left. Thus entry 0 contains the join operator for the join between
+** entries 0 and 1. Any ON or USING clauses associated with the join are
+** also attached to the left entry.
+**
+** This routine returns the number of errors encountered.
+*/
+static int sqliteProcessJoin(Parse *pParse, Select *p){
+ SrcList *pSrc; /* All tables in the FROM clause */
+ int i, j; /* Loop counters */
+ struct SrcList_item *pLeft; /* Left table being joined */
+ struct SrcList_item *pRight; /* Right table being joined */
+
+ pSrc = p->pSrc;
+ pLeft = &pSrc->a[0];
+ pRight = &pLeft[1];
+ for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
+ Table *pLeftTab = pLeft->pTab;
+ Table *pRightTab = pRight->pTab;
+ int isOuter;
+
+ if( pLeftTab==0 || pRightTab==0 ) continue;
+ isOuter = (pRight->jointype & JT_OUTER)!=0;
+
+ /* When the NATURAL keyword is present, add WHERE clause terms for
+ ** every column that the two tables have in common.
+ */
+ if( pRight->jointype & JT_NATURAL ){
+ if( pRight->pOn || pRight->pUsing ){
+ sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
+ "an ON or USING clause", 0);
+ return 1;
+ }
+ for(j=0; j<pLeftTab->nCol; j++){
+ char *zName = pLeftTab->aCol[j].zName;
+ if( columnIndex(pRightTab, zName)>=0 ){
+ addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias,
+ pRightTab, pRight->zAlias,
+ pRight->iCursor, &p->pWhere, isOuter);
+
+ }
+ }
+ }
+
+ /* Disallow both ON and USING clauses in the same join
+ */
+ if( pRight->pOn && pRight->pUsing ){
+ sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
+ "clauses in the same join");
+ return 1;
+ }
+
+ /* Add the ON clause to the end of the WHERE clause, connected by
+ ** an AND operator.
+ */
+ if( pRight->pOn ){
+ if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
+ p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
+ pRight->pOn = 0;
+ }
+
+ /* Create extra terms on the WHERE clause for each column named
+ ** in the USING clause. Example: If the two tables to be joined are
+ ** A and B and the USING clause names X, Y, and Z, then add this
+ ** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
+ ** Report an error if any column mentioned in the USING clause is
+ ** not contained in both tables to be joined.
+ */
+ if( pRight->pUsing ){
+ IdList *pList = pRight->pUsing;
+ for(j=0; j<pList->nId; j++){
+ char *zName = pList->a[j].zName;
+ if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
+ sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
+ "not present in both tables", zName);
+ return 1;
+ }
+ addWhereTerm(pParse, zName, pLeftTab, pLeft->zAlias,
+ pRightTab, pRight->zAlias,
+ pRight->iCursor, &p->pWhere, isOuter);
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+** Insert code into "v" that will push the record on the top of the
+** stack into the sorter.
+*/
+static void pushOntoSorter(
+ Parse *pParse, /* Parser context */
+ ExprList *pOrderBy, /* The ORDER BY clause */
+ Select *pSelect, /* The whole SELECT statement */
+ int regData /* Register holding data to be sorted */
+){
+ Vdbe *v = pParse->pVdbe;
+ int nExpr = pOrderBy->nExpr;
+ int regBase = sqlite3GetTempRange(pParse, nExpr+2);
+ int regRecord = sqlite3GetTempReg(pParse);
+ sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
+ sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
+ sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
+ sqlite3ReleaseTempReg(pParse, regRecord);
+ sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
+ if( pSelect->iLimit ){
+ int addr1, addr2;
+ int iLimit;
+ if( pSelect->iOffset ){
+ iLimit = pSelect->iOffset+1;
+ }else{
+ iLimit = pSelect->iLimit;
+ }
+ addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
+ sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
+ addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
+ sqlite3VdbeJumpHere(v, addr1);
+ sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
+ sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
+ sqlite3VdbeJumpHere(v, addr2);
+ pSelect->iLimit = 0;
+ }
+}
+
+/*
+** Add code to implement the OFFSET
+*/
+static void codeOffset(
+ Vdbe *v, /* Generate code into this VM */
+ Select *p, /* The SELECT statement being coded */
+ int iContinue /* Jump here to skip the current record */
+){
+ if( p->iOffset && iContinue!=0 ){
+ int addr;
+ sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
+ addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
+ VdbeComment((v, "skip OFFSET records"));
+ sqlite3VdbeJumpHere(v, addr);
+ }
+}
+
+/*
+** Add code that will check to make sure the N registers starting at iMem
+** form a distinct entry. iTab is a sorting index that holds previously
+** seen combinations of the N values. A new entry is made in iTab
+** if the current N values are new.
+**
+** A jump to addrRepeat is made and the N+1 values are popped from the
+** stack if the top N elements are not distinct.
+*/
+static void codeDistinct(
+ Parse *pParse, /* Parsing and code generating context */
+ int iTab, /* A sorting index used to test for distinctness */
+ int addrRepeat, /* Jump to here if not distinct */
+ int N, /* Number of elements */
+ int iMem /* First element */
+){
+ Vdbe *v;
+ int r1;
+
+ v = pParse->pVdbe;
+ r1 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
+ sqlite3VdbeAddOp3(v, OP_Found, iTab, addrRepeat, r1);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
+ sqlite3ReleaseTempReg(pParse, r1);
+}
+
+/*
+** Generate an error message when a SELECT is used within a subexpression
+** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
+** column. We do this in a subroutine because the error occurs in multiple
+** places.
+*/
+static int checkForMultiColumnSelectError(
+ Parse *pParse, /* Parse context. */
+ SelectDest *pDest, /* Destination of SELECT results */
+ int nExpr /* Number of result columns returned by SELECT */
+){
+ int eDest = pDest->eDest;
+ if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
+ sqlite3ErrorMsg(pParse, "only a single result allowed for "
+ "a SELECT that is part of an expression");
+ return 1;
+ }else{
+ return 0;
+ }
+}
+
+/*
+** This routine generates the code for the inside of the inner loop
+** of a SELECT.
+**
+** If srcTab and nColumn are both zero, then the pEList expressions
+** are evaluated in order to get the data for this row. If nColumn>0
+** then data is pulled from srcTab and pEList is used only to get the
+** datatypes for each column.
+*/
+static void selectInnerLoop(
+ Parse *pParse, /* The parser context */
+ Select *p, /* The complete select statement being coded */
+ ExprList *pEList, /* List of values being extracted */
+ int srcTab, /* Pull data from this table */
+ int nColumn, /* Number of columns in the source table */
+ ExprList *pOrderBy, /* If not NULL, sort results using this key */
+ int distinct, /* If >=0, make sure results are distinct */
+ SelectDest *pDest, /* How to dispose of the results */
+ int iContinue, /* Jump here to continue with next row */
+ int iBreak /* Jump here to break out of the inner loop */
+){
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ int hasDistinct; /* True if the DISTINCT keyword is present */
+ int regResult; /* Start of memory holding result set */
+ int eDest = pDest->eDest; /* How to dispose of results */
+ int iParm = pDest->iParm; /* First argument to disposal method */
+ int nResultCol; /* Number of result columns */
+
+ if( v==0 ) return;
+ assert( pEList!=0 );
+ hasDistinct = distinct>=0;
+ if( pOrderBy==0 && !hasDistinct ){
+ codeOffset(v, p, iContinue);
+ }
+
+ /* Pull the requested columns.
+ */
+ if( nColumn>0 ){
+ nResultCol = nColumn;
+ }else{
+ nResultCol = pEList->nExpr;
+ }
+ if( pDest->iMem==0 ){
+ pDest->iMem = pParse->nMem+1;
+ pDest->nMem = nResultCol;
+ pParse->nMem += nResultCol;
+ }else if( pDest->nMem!=nResultCol ){
+ /* This happens when two SELECTs of a compound SELECT have differing
+ ** numbers of result columns. The error message will be generated by
+ ** a higher-level routine. */
+ return;
+ }
+ regResult = pDest->iMem;
+ if( nColumn>0 ){
+ for(i=0; i<nColumn; i++){
+ sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
+ }
+ }else if( eDest!=SRT_Exists ){
+ /* If the destination is an EXISTS(...) expression, the actual
+ ** values returned by the SELECT are not required.
+ */
+ sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Callback);
+ }
+ nColumn = nResultCol;
+
+ /* If the DISTINCT keyword was present on the SELECT statement
+ ** and this row has been seen before, then do not make this row
+ ** part of the result.
+ */
+ if( hasDistinct ){
+ assert( pEList!=0 );
+ assert( pEList->nExpr==nColumn );
+ codeDistinct(pParse, distinct, iContinue, nColumn, regResult);
+ if( pOrderBy==0 ){
+ codeOffset(v, p, iContinue);
+ }
+ }
+
+ if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
+ return;
+ }
+
+ switch( eDest ){
+ /* In this mode, write each query result to the key of the temporary
+ ** table iParm.
+ */
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+ case SRT_Union: {
+ int r1;
+ r1 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
+ sqlite3ReleaseTempReg(pParse, r1);
+ break;
+ }
+
+ /* Construct a record from the query result, but instead of
+ ** saving that record, use it as a key to delete elements from
+ ** the temporary table iParm.
+ */
+ case SRT_Except: {
+ sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nColumn);
+ break;
+ }
+#endif
+
+ /* Store the result as data using a unique key.
+ */
+ case SRT_Table:
+ case SRT_EphemTab: {
+ int r1 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
+ if( pOrderBy ){
+ pushOntoSorter(pParse, pOrderBy, p, r1);
+ }else{
+ int r2 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
+ sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
+ sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+ sqlite3ReleaseTempReg(pParse, r2);
+ }
+ sqlite3ReleaseTempReg(pParse, r1);
+ break;
+ }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+ /* If we are creating a set for an "expr IN (SELECT ...)" construct,
+ ** then there should be a single item on the stack. Write this
+ ** item into the set table with bogus data.
+ */
+ case SRT_Set: {
+ assert( nColumn==1 );
+ p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
+ if( pOrderBy ){
+ /* At first glance you would think we could optimize out the
+ ** ORDER BY in this case since the order of entries in the set
+ ** does not matter. But there might be a LIMIT clause, in which
+ ** case the order does matter */
+ pushOntoSorter(pParse, pOrderBy, p, regResult);
+ }else{
+ int r1 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, 1, r1, &p->affinity, 1);
+ sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
+ sqlite3ReleaseTempReg(pParse, r1);
+ }
+ break;
+ }
+
+ /* If any row exist in the result set, record that fact and abort.
+ */
+ case SRT_Exists: {
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
+ /* The LIMIT clause will terminate the loop for us */
+ break;
+ }
+
+ /* If this is a scalar select that is part of an expression, then
+ ** store the results in the appropriate memory cell and break out
+ ** of the scan loop.
+ */
+ case SRT_Mem: {
+ assert( nColumn==1 );
+ if( pOrderBy ){
+ pushOntoSorter(pParse, pOrderBy, p, regResult);
+ }else{
+ sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
+ /* The LIMIT clause will jump out of the loop for us */
+ }
+ break;
+ }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+ /* Send the data to the callback function or to a subroutine. In the
+ ** case of a subroutine, the subroutine itself is responsible for
+ ** popping the data from the stack.
+ */
+ case SRT_Coroutine:
+ case SRT_Callback: {
+ if( pOrderBy ){
+ int r1 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
+ pushOntoSorter(pParse, pOrderBy, p, r1);
+ sqlite3ReleaseTempReg(pParse, r1);
+ }else if( eDest==SRT_Coroutine ){
+ sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
+ }else{
+ sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
+ sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
+ }
+ break;
+ }
+
+#if !defined(SQLITE_OMIT_TRIGGER)
+ /* Discard the results. This is used for SELECT statements inside
+ ** the body of a TRIGGER. The purpose of such selects is to call
+ ** user-defined functions that have side effects. We do not care
+ ** about the actual results of the select.
+ */
+ default: {
+ assert( eDest==SRT_Discard );
+ break;
+ }
+#endif
+ }
+
+ /* Jump to the end of the loop if the LIMIT is reached.
+ */
+ if( p->iLimit ){
+ assert( pOrderBy==0 ); /* If there is an ORDER BY, the call to
+ ** pushOntoSorter() would have cleared p->iLimit */
+ sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+ sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+ }
+}
+
+/*
+** Given an expression list, generate a KeyInfo structure that records
+** the collating sequence for each expression in that expression list.
+**
+** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
+** KeyInfo structure is appropriate for initializing a virtual index to
+** implement that clause. If the ExprList is the result set of a SELECT
+** then the KeyInfo structure is appropriate for initializing a virtual
+** index to implement a DISTINCT test.
+**
+** Space to hold the KeyInfo structure is obtain from malloc. The calling
+** function is responsible for seeing that this structure is eventually
+** freed. Add the KeyInfo structure to the P4 field of an opcode using
+** P4_KEYINFO_HANDOFF is the usual way of dealing with this.
+*/
+static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
+ sqlite3 *db = pParse->db;
+ int nExpr;
+ KeyInfo *pInfo;
+ struct ExprList_item *pItem;
+ int i;
+
+ nExpr = pList->nExpr;
+ pInfo = sqlite3DbMallocZero(db, sizeof(*pInfo) + nExpr*(sizeof(CollSeq*)+1) );
+ if( pInfo ){
+ pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
+ pInfo->nField = nExpr;
+ pInfo->enc = ENC(db);
+ for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
+ CollSeq *pColl;
+ pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
+ if( !pColl ){
+ pColl = db->pDfltColl;
+ }
+ pInfo->aColl[i] = pColl;
+ pInfo->aSortOrder[i] = pItem->sortOrder;
+ }
+ }
+ return pInfo;
+}
+
+
+/*
+** If the inner loop was generated using a non-null pOrderBy argument,
+** then the results were placed in a sorter. After the loop is terminated
+** we need to run the sorter and output the results. The following
+** routine generates the code needed to do that.
+*/
+static void generateSortTail(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The SELECT statement */
+ Vdbe *v, /* Generate code into this VDBE */
+ int nColumn, /* Number of columns of data */
+ SelectDest *pDest /* Write the sorted results here */
+){
+ int brk = sqlite3VdbeMakeLabel(v);
+ int cont = sqlite3VdbeMakeLabel(v);
+ int addr;
+ int iTab;
+ int pseudoTab = 0;
+ ExprList *pOrderBy = p->pOrderBy;
+
+ int eDest = pDest->eDest;
+ int iParm = pDest->iParm;
+
+ int regRow;
+ int regRowid;
+
+ iTab = pOrderBy->iECursor;
+ if( eDest==SRT_Callback || eDest==SRT_Coroutine ){
+ pseudoTab = pParse->nTab++;
+ sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, nColumn);
+ sqlite3VdbeAddOp2(v, OP_OpenPseudo, pseudoTab, eDest==SRT_Callback);
+ }
+ addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, brk);
+ codeOffset(v, p, cont);
+ regRow = sqlite3GetTempReg(pParse);
+ regRowid = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr + 1, regRow);
+ switch( eDest ){
+ case SRT_Table:
+ case SRT_EphemTab: {
+ sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
+ sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
+ sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+ break;
+ }
+#ifndef SQLITE_OMIT_SUBQUERY
+ case SRT_Set: {
+ assert( nColumn==1 );
+ sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid, &p->affinity, 1);
+ sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
+ break;
+ }
+ case SRT_Mem: {
+ assert( nColumn==1 );
+ sqlite3ExprCodeMove(pParse, regRow, iParm, 1);
+ /* The LIMIT clause will terminate the loop for us */
+ break;
+ }
+#endif
+ case SRT_Callback:
+ case SRT_Coroutine: {
+ int i;
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, regRowid);
+ sqlite3VdbeAddOp3(v, OP_Insert, pseudoTab, regRow, regRowid);
+ for(i=0; i<nColumn; i++){
+ assert( regRow!=pDest->iMem+i );
+ sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
+ }
+ if( eDest==SRT_Callback ){
+ sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
+ sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
+ }else{
+ sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
+ }
+ break;
+ }
+ default: {
+ /* Do nothing */
+ break;
+ }
+ }
+ sqlite3ReleaseTempReg(pParse, regRow);
+ sqlite3ReleaseTempReg(pParse, regRowid);
+
+ /* LIMIT has been implemented by the pushOntoSorter() routine.
+ */
+ assert( p->iLimit==0 );
+
+ /* The bottom of the loop
+ */
+ sqlite3VdbeResolveLabel(v, cont);
+ sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
+ sqlite3VdbeResolveLabel(v, brk);
+ if( eDest==SRT_Callback || eDest==SRT_Coroutine ){
+ sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
+ }
+
+}
+
+/*
+** Return a pointer to a string containing the 'declaration type' of the
+** expression pExpr. The string may be treated as static by the caller.
+**
+** The declaration type is the exact datatype definition extracted from the
+** original CREATE TABLE statement if the expression is a column. The
+** declaration type for a ROWID field is INTEGER. Exactly when an expression
+** is considered a column can be complex in the presence of subqueries. The
+** result-set expression in all of the following SELECT statements is
+** considered a column by this function.
+**
+** SELECT col FROM tbl;
+** SELECT (SELECT col FROM tbl;
+** SELECT (SELECT col FROM tbl);
+** SELECT abc FROM (SELECT col AS abc FROM tbl);
+**
+** The declaration type for any expression other than a column is NULL.
+*/
+static const char *columnType(
+ NameContext *pNC,
+ Expr *pExpr,
+ const char **pzOriginDb,
+ const char **pzOriginTab,
+ const char **pzOriginCol
+){
+ char const *zType = 0;
+ char const *zOriginDb = 0;
+ char const *zOriginTab = 0;
+ char const *zOriginCol = 0;
+ int j;
+ if( pExpr==0 || pNC->pSrcList==0 ) return 0;
+
+ switch( pExpr->op ){
+ case TK_AGG_COLUMN:
+ case TK_COLUMN: {
+ /* The expression is a column. Locate the table the column is being
+ ** extracted from in NameContext.pSrcList. This table may be real
+ ** database table or a subquery.
+ */
+ Table *pTab = 0; /* Table structure column is extracted from */
+ Select *pS = 0; /* Select the column is extracted from */
+ int iCol = pExpr->iColumn; /* Index of column in pTab */
+ while( pNC && !pTab ){
+ SrcList *pTabList = pNC->pSrcList;
+ for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
+ if( j<pTabList->nSrc ){
+ pTab = pTabList->a[j].pTab;
+ pS = pTabList->a[j].pSelect;
+ }else{
+ pNC = pNC->pNext;
+ }
+ }
+
+ if( pTab==0 ){
+ /* FIX ME:
+ ** This can occurs if you have something like "SELECT new.x;" inside
+ ** a trigger. In other words, if you reference the special "new"
+ ** table in the result set of a select. We do not have a good way
+ ** to find the actual table type, so call it "TEXT". This is really
+ ** something of a bug, but I do not know how to fix it.
+ **
+ ** This code does not produce the correct answer - it just prevents
+ ** a segfault. See ticket #1229.
+ */
+ zType = "TEXT";
+ break;
+ }
+
+ assert( pTab );
+ if( pS ){
+ /* The "table" is actually a sub-select or a view in the FROM clause
+ ** of the SELECT statement. Return the declaration type and origin
+ ** data for the result-set column of the sub-select.
+ */
+ if( iCol>=0 && iCol<pS->pEList->nExpr ){
+ /* If iCol is less than zero, then the expression requests the
+ ** rowid of the sub-select or view. This expression is legal (see
+ ** test case misc2.2.2) - it always evaluates to NULL.
+ */
+ NameContext sNC;
+ Expr *p = pS->pEList->a[iCol].pExpr;
+ sNC.pSrcList = pS->pSrc;
+ sNC.pNext = 0;
+ sNC.pParse = pNC->pParse;
+ zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
+ }
+ }else if( pTab->pSchema ){
+ /* A real table */
+ assert( !pS );
+ if( iCol<0 ) iCol = pTab->iPKey;
+ assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+ if( iCol<0 ){
+ zType = "INTEGER";
+ zOriginCol = "rowid";
+ }else{
+ zType = pTab->aCol[iCol].zType;
+ zOriginCol = pTab->aCol[iCol].zName;
+ }
+ zOriginTab = pTab->zName;
+ if( pNC->pParse ){
+ int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
+ zOriginDb = pNC->pParse->db->aDb[iDb].zName;
+ }
+ }
+ break;
+ }
+#ifndef SQLITE_OMIT_SUBQUERY
+ case TK_SELECT: {
+ /* The expression is a sub-select. Return the declaration type and
+ ** origin info for the single column in the result set of the SELECT
+ ** statement.
+ */
+ NameContext sNC;
+ Select *pS = pExpr->pSelect;
+ Expr *p = pS->pEList->a[0].pExpr;
+ sNC.pSrcList = pS->pSrc;
+ sNC.pNext = pNC;
+ sNC.pParse = pNC->pParse;
+ zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
+ break;
+ }
+#endif
+ }
+
+ if( pzOriginDb ){
+ assert( pzOriginTab && pzOriginCol );
+ *pzOriginDb = zOriginDb;
+ *pzOriginTab = zOriginTab;
+ *pzOriginCol = zOriginCol;
+ }
+ return zType;
+}
+
+/*
+** Generate code that will tell the VDBE the declaration types of columns
+** in the result set.
+*/
+static void generateColumnTypes(
+ Parse *pParse, /* Parser context */
+ SrcList *pTabList, /* List of tables */
+ ExprList *pEList /* Expressions defining the result set */
+){
+#ifndef SQLITE_OMIT_DECLTYPE
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ NameContext sNC;
+ sNC.pSrcList = pTabList;
+ sNC.pParse = pParse;
+ for(i=0; i<pEList->nExpr; i++){
+ Expr *p = pEList->a[i].pExpr;
+ const char *zType;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+ const char *zOrigDb = 0;
+ const char *zOrigTab = 0;
+ const char *zOrigCol = 0;
+ zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
+
+ /* The vdbe must make its own copy of the column-type and other
+ ** column specific strings, in case the schema is reset before this
+ ** virtual machine is deleted.
+ */
+ sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P4_TRANSIENT);
+ sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P4_TRANSIENT);
+ sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P4_TRANSIENT);
+#else
+ zType = columnType(&sNC, p, 0, 0, 0);
+#endif
+ sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, P4_TRANSIENT);
+ }
+#endif /* SQLITE_OMIT_DECLTYPE */
+}
+
+/*
+** Generate code that will tell the VDBE the names of columns
+** in the result set. This information is used to provide the
+** azCol[] values in the callback.
+*/
+static void generateColumnNames(
+ Parse *pParse, /* Parser context */
+ SrcList *pTabList, /* List of tables */
+ ExprList *pEList /* Expressions defining the result set */
+){
+ Vdbe *v = pParse->pVdbe;
+ int i, j;
+ sqlite3 *db = pParse->db;
+ int fullNames, shortNames;
+
+#ifndef SQLITE_OMIT_EXPLAIN
+ /* If this is an EXPLAIN, skip this step */
+ if( pParse->explain ){
+ return;
+ }
+#endif
+
+ assert( v!=0 );
+ if( pParse->colNamesSet || v==0 || db->mallocFailed ) return;
+ pParse->colNamesSet = 1;
+ fullNames = (db->flags & SQLITE_FullColNames)!=0;
+ shortNames = (db->flags & SQLITE_ShortColNames)!=0;
+ sqlite3VdbeSetNumCols(v, pEList->nExpr);
+ for(i=0; i<pEList->nExpr; i++){
+ Expr *p;
+ p = pEList->a[i].pExpr;
+ if( p==0 ) continue;
+ if( pEList->a[i].zName ){
+ char *zName = pEList->a[i].zName;
+ sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, strlen(zName));
+ }else if( p->op==TK_COLUMN && pTabList ){
+ Table *pTab;
+ char *zCol;
+ int iCol = p->iColumn;
+ for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
+ assert( j<pTabList->nSrc );
+ pTab = pTabList->a[j].pTab;
+ if( iCol<0 ) iCol = pTab->iPKey;
+ assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+ if( iCol<0 ){
+ zCol = "rowid";
+ }else{
+ zCol = pTab->aCol[iCol].zName;
+ }
+ if( !shortNames && !fullNames ){
+ sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
+ }else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
+ char *zName = 0;
+ char *zTab;
+
+ zTab = pTabList->a[j].zAlias;
+ if( fullNames || zTab==0 ) zTab = pTab->zName;
+ zName = sqlite3MPrintf(db, "%s.%s", zTab, zCol);
+ sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P4_DYNAMIC);
+ }else{
+ sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
+ }
+ }else{
+ sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
+ }
+ }
+ generateColumnTypes(pParse, pTabList, pEList);
+}
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Name of the connection operator, used for error messages.
+*/
+static const char *selectOpName(int id){
+ char *z;
+ switch( id ){
+ case TK_ALL: z = "UNION ALL"; break;
+ case TK_INTERSECT: z = "INTERSECT"; break;
+ case TK_EXCEPT: z = "EXCEPT"; break;
+ default: z = "UNION"; break;
+ }
+ return z;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+/*
+** Forward declaration
+*/
+static int prepSelectStmt(Parse*, Select*);
+
+/*
+** Given a SELECT statement, generate a Table structure that describes
+** the result set of that SELECT.
+*/
+Table *sqlite3ResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
+ Table *pTab;
+ int i, j, rc;
+ ExprList *pEList;
+ Column *aCol, *pCol;
+ sqlite3 *db = pParse->db;
+ int savedFlags;
+
+ savedFlags = db->flags;
+ db->flags &= ~SQLITE_FullColNames;
+ db->flags |= SQLITE_ShortColNames;
+ rc = sqlite3SelectResolve(pParse, pSelect, 0);
+ if( rc==SQLITE_OK ){
+ while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+ rc = prepSelectStmt(pParse, pSelect);
+ if( rc==SQLITE_OK ){
+ rc = sqlite3SelectResolve(pParse, pSelect, 0);
+ }
+ }
+ db->flags = savedFlags;
+ if( rc ){
+ return 0;
+ }
+ pTab = sqlite3DbMallocZero(db, sizeof(Table) );
+ if( pTab==0 ){
+ return 0;
+ }
+ pTab->db = db;
+ pTab->nRef = 1;
+ pTab->zName = zTabName ? sqlite3DbStrDup(db, zTabName) : 0;
+ pEList = pSelect->pEList;
+ pTab->nCol = pEList->nExpr;
+ assert( pTab->nCol>0 );
+ pTab->aCol = aCol = sqlite3DbMallocZero(db, sizeof(pTab->aCol[0])*pTab->nCol);
+ testcase( aCol==0 );
+ for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
+ Expr *p;
+ char *zType;
+ char *zName;
+ int nName;
+ CollSeq *pColl;
+ int cnt;
+ NameContext sNC;
+
+ /* Get an appropriate name for the column
+ */
+ p = pEList->a[i].pExpr;
+ assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
+ if( (zName = pEList->a[i].zName)!=0 ){
+ /* If the column contains an "AS <name>" phrase, use <name> as the name */
+ zName = sqlite3DbStrDup(db, zName);
+ }else if( p->op==TK_COLUMN && p->pTab ){
+ /* For columns use the column name name */
+ int iCol = p->iColumn;
+ if( iCol<0 ) iCol = p->pTab->iPKey;
+ zName = sqlite3MPrintf(db, "%s", p->pTab->aCol[iCol].zName);
+ }else{
+ /* Use the original text of the column expression as its name */
+ zName = sqlite3MPrintf(db, "%T", &p->span);
+ }
+ if( db->mallocFailed ){
+ sqlite3DbFree(db, zName);
+ break;
+ }
+ sqlite3Dequote(zName);
+
+ /* Make sure the column name is unique. If the name is not unique,
+ ** append a integer to the name so that it becomes unique.
+ */
+ nName = strlen(zName);
+ for(j=cnt=0; j<i; j++){
+ if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
+ char *zNewName;
+ zName[nName] = 0;
+ zNewName = sqlite3MPrintf(db, "%s:%d", zName, ++cnt);
+ sqlite3DbFree(db, zName);
+ zName = zNewName;
+ j = -1;
+ if( zName==0 ) break;
+ }
+ }
+ pCol->zName = zName;
+
+ /* Get the typename, type affinity, and collating sequence for the
+ ** column.
+ */
+ memset(&sNC, 0, sizeof(sNC));
+ sNC.pSrcList = pSelect->pSrc;
+ zType = sqlite3DbStrDup(db, columnType(&sNC, p, 0, 0, 0));
+ pCol->zType = zType;
+ pCol->affinity = sqlite3ExprAffinity(p);
+ pColl = sqlite3ExprCollSeq(pParse, p);
+ if( pColl ){
+ pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
+ }
+ }
+ pTab->iPKey = -1;
+ if( db->mallocFailed ){
+ sqlite3DeleteTable(pTab);
+ return 0;
+ }
+ return pTab;
+}
+
+/*
+** Prepare a SELECT statement for processing by doing the following
+** things:
+**
+** (1) Make sure VDBE cursor numbers have been assigned to every
+** element of the FROM clause.
+**
+** (2) Fill in the pTabList->a[].pTab fields in the SrcList that
+** defines FROM clause. When views appear in the FROM clause,
+** fill pTabList->a[].pSelect with a copy of the SELECT statement
+** that implements the view. A copy is made of the view's SELECT
+** statement so that we can freely modify or delete that statement
+** without worrying about messing up the presistent representation
+** of the view.
+**
+** (3) Add terms to the WHERE clause to accomodate the NATURAL keyword
+** on joins and the ON and USING clause of joins.
+**
+** (4) Scan the list of columns in the result set (pEList) looking
+** for instances of the "*" operator or the TABLE.* operator.
+** If found, expand each "*" to be every column in every table
+** and TABLE.* to be every column in TABLE.
+**
+** Return 0 on success. If there are problems, leave an error message
+** in pParse and return non-zero.
+*/
+static int prepSelectStmt(Parse *pParse, Select *p){
+ int i, j, k, rc;
+ SrcList *pTabList;
+ ExprList *pEList;
+ struct SrcList_item *pFrom;
+ sqlite3 *db = pParse->db;
+
+ if( p==0 || p->pSrc==0 || db->mallocFailed ){
+ return 1;
+ }
+ pTabList = p->pSrc;
+ pEList = p->pEList;
+
+ /* Make sure cursor numbers have been assigned to all entries in
+ ** the FROM clause of the SELECT statement.
+ */
+ sqlite3SrcListAssignCursors(pParse, p->pSrc);
+
+ /* Look up every table named in the FROM clause of the select. If
+ ** an entry of the FROM clause is a subquery instead of a table or view,
+ ** then create a transient table structure to describe the subquery.
+ */
+ for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+ Table *pTab;
+ if( pFrom->pTab!=0 ){
+ /* This statement has already been prepared. There is no need
+ ** to go further. */
+ assert( i==0 );
+ return 0;
+ }
+ if( pFrom->zName==0 ){
+#ifndef SQLITE_OMIT_SUBQUERY
+ /* A sub-query in the FROM clause of a SELECT */
+ assert( pFrom->pSelect!=0 );
+ if( pFrom->zAlias==0 ){
+ pFrom->zAlias =
+ sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pFrom->pSelect);
+ }
+ assert( pFrom->pTab==0 );
+ pFrom->pTab = pTab =
+ sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
+ if( pTab==0 ){
+ return 1;
+ }
+ /* The isEphem flag indicates that the Table structure has been
+ ** dynamically allocated and may be freed at any time. In other words,
+ ** pTab is not pointing to a persistent table structure that defines
+ ** part of the schema. */
+ pTab->isEphem = 1;
+#endif
+ }else{
+ /* An ordinary table or view name in the FROM clause */
+ assert( pFrom->pTab==0 );
+ pFrom->pTab = pTab =
+ sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);
+ if( pTab==0 ){
+ return 1;
+ }
+ pTab->nRef++;
+#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
+ if( pTab->pSelect || IsVirtual(pTab) ){
+ /* We reach here if the named table is a really a view */
+ if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+ return 1;
+ }
+ /* If pFrom->pSelect!=0 it means we are dealing with a
+ ** view within a view. The SELECT structure has already been
+ ** copied by the outer view so we can skip the copy step here
+ ** in the inner view.
+ */
+ if( pFrom->pSelect==0 ){
+ pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect);
+ }
+ }
+#endif
+ }
+ }
+
+ /* Process NATURAL keywords, and ON and USING clauses of joins.
+ */
+ if( sqliteProcessJoin(pParse, p) ) return 1;
+
+ /* For every "*" that occurs in the column list, insert the names of
+ ** all columns in all tables. And for every TABLE.* insert the names
+ ** of all columns in TABLE. The parser inserted a special expression
+ ** with the TK_ALL operator for each "*" that it found in the column list.
+ ** The following code just has to locate the TK_ALL expressions and expand
+ ** each one to the list of all columns in all tables.
+ **
+ ** The first loop just checks to see if there are any "*" operators
+ ** that need expanding.
+ */
+ for(k=0; k<pEList->nExpr; k++){
+ Expr *pE = pEList->a[k].pExpr;
+ if( pE->op==TK_ALL ) break;
+ if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
+ && pE->pLeft && pE->pLeft->op==TK_ID ) break;
+ }
+ rc = 0;
+ if( k<pEList->nExpr ){
+ /*
+ ** If we get here it means the result set contains one or more "*"
+ ** operators that need to be expanded. Loop through each expression
+ ** in the result set and expand them one by one.
+ */
+ struct ExprList_item *a = pEList->a;
+ ExprList *pNew = 0;
+ int flags = pParse->db->flags;
+ int longNames = (flags & SQLITE_FullColNames)!=0
+ && (flags & SQLITE_ShortColNames)==0;
+
+ for(k=0; k<pEList->nExpr; k++){
+ Expr *pE = a[k].pExpr;
+ if( pE->op!=TK_ALL &&
+ (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
+ /* This particular expression does not need to be expanded.
+ */
+ pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr, 0);
+ if( pNew ){
+ pNew->a[pNew->nExpr-1].zName = a[k].zName;
+ }else{
+ rc = 1;
+ }
+ a[k].pExpr = 0;
+ a[k].zName = 0;
+ }else{
+ /* This expression is a "*" or a "TABLE.*" and needs to be
+ ** expanded. */
+ int tableSeen = 0; /* Set to 1 when TABLE matches */
+ char *zTName; /* text of name of TABLE */
+ if( pE->op==TK_DOT && pE->pLeft ){
+ zTName = sqlite3NameFromToken(db, &pE->pLeft->token);
+ }else{
+ zTName = 0;
+ }
+ for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+ Table *pTab = pFrom->pTab;
+ char *zTabName = pFrom->zAlias;
+ if( zTabName==0 || zTabName[0]==0 ){
+ zTabName = pTab->zName;
+ }
+ assert( zTabName );
+ if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
+ continue;
+ }
+ tableSeen = 1;
+ for(j=0; j<pTab->nCol; j++){
+ Expr *pExpr, *pRight;
+ char *zName = pTab->aCol[j].zName;
+
+ /* If a column is marked as 'hidden' (currently only possible
+ ** for virtual tables), do not include it in the expanded
+ ** result-set list.
+ */
+ if( IsHiddenColumn(&pTab->aCol[j]) ){
+ assert(IsVirtual(pTab));
+ continue;
+ }
+
+ if( i>0 ){
+ struct SrcList_item *pLeft = &pTabList->a[i-1];
+ if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
+ columnIndex(pLeft->pTab, zName)>=0 ){
+ /* In a NATURAL join, omit the join columns from the
+ ** table on the right */
+ continue;
+ }
+ if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
+ /* In a join with a USING clause, omit columns in the
+ ** using clause from the table on the right. */
+ continue;
+ }
+ }
+ pRight = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
+ if( pRight==0 ) break;
+ setQuotedToken(pParse, &pRight->token, zName);
+ if( longNames || pTabList->nSrc>1 ){
+ Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
+ pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
+ if( pExpr==0 ) break;
+ setQuotedToken(pParse, &pLeft->token, zTabName);
+#if 1
+ setToken(&pExpr->span,
+ sqlite3MPrintf(db, "%s.%s", zTabName, zName));
+ pExpr->span.dyn = 1;
+#else
+ pExpr->span = pRight->token;
+ pExpr->span.dyn = 0;
+#endif
+ pExpr->token.z = 0;
+ pExpr->token.n = 0;
+ pExpr->token.dyn = 0;
+ }else{
+ pExpr = pRight;
+ pExpr->span = pExpr->token;
+ pExpr->span.dyn = 0;
+ }
+ if( longNames ){
+ pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pExpr->span);
+ }else{
+ pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pRight->token);
+ }
+ }
+ }
+ if( !tableSeen ){
+ if( zTName ){
+ sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
+ }else{
+ sqlite3ErrorMsg(pParse, "no tables specified");
+ }
+ rc = 1;
+ }
+ sqlite3DbFree(db, zTName);
+ }
+ }
+ sqlite3ExprListDelete(db, pEList);
+ p->pEList = pNew;
+ }
+#if SQLITE_MAX_COLUMN
+ if( p->pEList && p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+ sqlite3ErrorMsg(pParse, "too many columns in result set");
+ rc = SQLITE_ERROR;
+ }
+#endif
+ if( db->mallocFailed ){
+ rc = SQLITE_NOMEM;
+ }
+ return rc;
+}
+
+/*
+** pE is a pointer to an expression which is a single term in
+** ORDER BY or GROUP BY clause.
+**
+** At the point this routine is called, we already know that the
+** ORDER BY term is not an integer index into the result set. That
+** casee is handled by the calling routine.
+**
+** If pE is a well-formed expression and the SELECT statement
+** is not compound, then return 0. This indicates to the
+** caller that it should sort by the value of the ORDER BY
+** expression.
+**
+** If the SELECT is compound, then attempt to match pE against
+** result set columns in the left-most SELECT statement. Return
+** the index i of the matching column, as an indication to the
+** caller that it should sort by the i-th column. If there is
+** no match, return -1 and leave an error message in pParse.
+*/
+static int matchOrderByTermToExprList(
+ Parse *pParse, /* Parsing context for error messages */
+ Select *pSelect, /* The SELECT statement with the ORDER BY clause */
+ Expr *pE, /* The specific ORDER BY term */
+ int idx, /* When ORDER BY term is this */
+ int isCompound, /* True if this is a compound SELECT */
+ u8 *pHasAgg /* True if expression contains aggregate functions */
+){
+ int i; /* Loop counter */
+ ExprList *pEList; /* The columns of the result set */
+ NameContext nc; /* Name context for resolving pE */
+
+ assert( sqlite3ExprIsInteger(pE, &i)==0 );
+ pEList = pSelect->pEList;
+
+ /* If the term is a simple identifier that try to match that identifier
+ ** against a column name in the result set.
+ */
+ if( pE->op==TK_ID || (pE->op==TK_STRING && pE->token.z[0]!='\'') ){
+ sqlite3 *db = pParse->db;
+ char *zCol = sqlite3NameFromToken(db, &pE->token);
+ if( zCol==0 ){
+ return -1;
+ }
+ for(i=0; i<pEList->nExpr; i++){
+ char *zAs = pEList->a[i].zName;
+ if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
+ sqlite3DbFree(db, zCol);
+ return i+1;
+ }
+ }
+ sqlite3DbFree(db, zCol);
+ }
+
+ /* Resolve all names in the ORDER BY term expression
+ */
+ memset(&nc, 0, sizeof(nc));
+ nc.pParse = pParse;
+ nc.pSrcList = pSelect->pSrc;
+ nc.pEList = pEList;
+ nc.allowAgg = 1;
+ nc.nErr = 0;
+ if( sqlite3ExprResolveNames(&nc, pE) ){
+ if( isCompound ){
+ sqlite3ErrorClear(pParse);
+ return 0;
+ }else{
+ return -1;
+ }
+ }
+ if( nc.hasAgg && pHasAgg ){
+ *pHasAgg = 1;
+ }
+
+ /* For a compound SELECT, we need to try to match the ORDER BY
+ ** expression against an expression in the result set
+ */
+ if( isCompound ){
+ for(i=0; i<pEList->nExpr; i++){
+ if( sqlite3ExprCompare(pEList->a[i].pExpr, pE) ){
+ return i+1;
+ }
+ }
+ }
+ return 0;
+}
+
+
+/*
+** Analyze and ORDER BY or GROUP BY clause in a simple SELECT statement.
+** Return the number of errors seen.
+**
+** Every term of the ORDER BY or GROUP BY clause needs to be an
+** expression. If any expression is an integer constant, then
+** that expression is replaced by the corresponding
+** expression from the result set.
+*/
+static int processOrderGroupBy(
+ Parse *pParse, /* Parsing context. Leave error messages here */
+ Select *pSelect, /* The SELECT statement containing the clause */
+ ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
+ int isOrder, /* 1 for ORDER BY. 0 for GROUP BY */
+ u8 *pHasAgg /* Set to TRUE if any term contains an aggregate */
+){
+ int i;
+ sqlite3 *db = pParse->db;
+ ExprList *pEList;
+
+ if( pOrderBy==0 || pParse->db->mallocFailed ) return 0;
+#if SQLITE_MAX_COLUMN
+ if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+ const char *zType = isOrder ? "ORDER" : "GROUP";
+ sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
+ return 1;
+ }
+#endif
+ pEList = pSelect->pEList;
+ if( pEList==0 ){
+ return 0;
+ }
+ for(i=0; i<pOrderBy->nExpr; i++){
+ int iCol;
+ Expr *pE = pOrderBy->a[i].pExpr;
+ if( sqlite3ExprIsInteger(pE, &iCol) ){
+ if( iCol<=0 || iCol>pEList->nExpr ){
+ const char *zType = isOrder ? "ORDER" : "GROUP";
+ sqlite3ErrorMsg(pParse,
+ "%r %s BY term out of range - should be "
+ "between 1 and %d", i+1, zType, pEList->nExpr);
+ return 1;
+ }
+ }else{
+ iCol = matchOrderByTermToExprList(pParse, pSelect, pE, i+1, 0, pHasAgg);
+ if( iCol<0 ){
+ return 1;
+ }
+ }
+ if( iCol>0 ){
+ CollSeq *pColl = pE->pColl;
+ int flags = pE->flags & EP_ExpCollate;
+ sqlite3ExprDelete(db, pE);
+ pE = sqlite3ExprDup(db, pEList->a[iCol-1].pExpr);
+ pOrderBy->a[i].pExpr = pE;
+ if( pE && pColl && flags ){
+ pE->pColl = pColl;
+ pE->flags |= flags;
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+** Analyze and ORDER BY or GROUP BY clause in a SELECT statement. Return
+** the number of errors seen.
+**
+** If iTable>0 then make the N-th term of the ORDER BY clause refer to
+** the N-th column of table iTable.
+**
+** If iTable==0 then transform each term of the ORDER BY clause to refer
+** to a column of the result set by number.
+*/
+static int processCompoundOrderBy(
+ Parse *pParse, /* Parsing context. Leave error messages here */
+ Select *pSelect /* The SELECT statement containing the ORDER BY */
+){
+ int i;
+ ExprList *pOrderBy;
+ ExprList *pEList;
+ sqlite3 *db;
+ int moreToDo = 1;
+
+ pOrderBy = pSelect->pOrderBy;
+ if( pOrderBy==0 ) return 0;
+ db = pParse->db;
+#if SQLITE_MAX_COLUMN
+ if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+ sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
+ return 1;
+ }
+#endif
+ for(i=0; i<pOrderBy->nExpr; i++){
+ pOrderBy->a[i].done = 0;
+ }
+ while( pSelect->pPrior ){
+ pSelect = pSelect->pPrior;
+ }
+ while( pSelect && moreToDo ){
+ moreToDo = 0;
+ pEList = pSelect->pEList;
+ if( pEList==0 ){
+ return 1;
+ }
+ for(i=0; i<pOrderBy->nExpr; i++){
+ int iCol = -1;
+ Expr *pE, *pDup;
+ if( pOrderBy->a[i].done ) continue;
+ pE = pOrderBy->a[i].pExpr;
+ if( sqlite3ExprIsInteger(pE, &iCol) ){
+ if( iCol<0 || iCol>pEList->nExpr ){
+ sqlite3ErrorMsg(pParse,
+ "%r ORDER BY term out of range - should be "
+ "between 1 and %d", i+1, pEList->nExpr);
+ return 1;
+ }
+ }else{
+ pDup = sqlite3ExprDup(db, pE);
+ if( !db->mallocFailed ){
+ assert(pDup);
+ iCol = matchOrderByTermToExprList(pParse, pSelect, pDup, i+1, 1, 0);
+ }
+ sqlite3ExprDelete(db, pDup);
+ if( iCol<0 ){
+ return 1;
+ }
+ }
+ if( iCol>0 ){
+ pE->op = TK_INTEGER;
+ pE->flags |= EP_IntValue;
+ pE->iTable = iCol;
+ pOrderBy->a[i].done = 1;
+ }else{
+ moreToDo = 1;
+ }
+ }
+ pSelect = pSelect->pNext;
+ }
+ for(i=0; i<pOrderBy->nExpr; i++){
+ if( pOrderBy->a[i].done==0 ){
+ sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any "
+ "column in the result set", i+1);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/*
+** Get a VDBE for the given parser context. Create a new one if necessary.
+** If an error occurs, return NULL and leave a message in pParse.
+*/
+Vdbe *sqlite3GetVdbe(Parse *pParse){
+ Vdbe *v = pParse->pVdbe;
+ if( v==0 ){
+ v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
+#ifndef SQLITE_OMIT_TRACE
+ if( v ){
+ sqlite3VdbeAddOp0(v, OP_Trace);
+ }
+#endif
+ }
+ return v;
+}
+
+
+/*
+** Compute the iLimit and iOffset fields of the SELECT based on the
+** pLimit and pOffset expressions. pLimit and pOffset hold the expressions
+** that appear in the original SQL statement after the LIMIT and OFFSET
+** keywords. Or NULL if those keywords are omitted. iLimit and iOffset
+** are the integer memory register numbers for counters used to compute
+** the limit and offset. If there is no limit and/or offset, then
+** iLimit and iOffset are negative.
+**
+** This routine changes the values of iLimit and iOffset only if
+** a limit or offset is defined by pLimit and pOffset. iLimit and
+** iOffset should have been preset to appropriate default values
+** (usually but not always -1) prior to calling this routine.
+** Only if pLimit!=0 or pOffset!=0 do the limit registers get
+** redefined. The UNION ALL operator uses this property to force
+** the reuse of the same limit and offset registers across multiple
+** SELECT statements.
+*/
+static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
+ Vdbe *v = 0;
+ int iLimit = 0;
+ int iOffset;
+ int addr1;
+ if( p->iLimit ) return;
+
+ /*
+ ** "LIMIT -1" always shows all rows. There is some
+ ** contraversy about what the correct behavior should be.
+ ** The current implementation interprets "LIMIT 0" to mean
+ ** no rows.
+ */
+ if( p->pLimit ){
+ p->iLimit = iLimit = ++pParse->nMem;
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ) return;
+ sqlite3ExprCode(pParse, p->pLimit, iLimit);
+ sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
+ VdbeComment((v, "LIMIT counter"));
+ sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
+ }
+ if( p->pOffset ){
+ p->iOffset = iOffset = ++pParse->nMem;
+ if( p->pLimit ){
+ pParse->nMem++; /* Allocate an extra register for limit+offset */
+ }
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ) return;
+ sqlite3ExprCode(pParse, p->pOffset, iOffset);
+ sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
+ VdbeComment((v, "OFFSET counter"));
+ addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
+ sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
+ sqlite3VdbeJumpHere(v, addr1);
+ if( p->pLimit ){
+ sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
+ VdbeComment((v, "LIMIT+OFFSET"));
+ addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
+ sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
+ sqlite3VdbeJumpHere(v, addr1);
+ }
+ }
+}
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Return the appropriate collating sequence for the iCol-th column of
+** the result set for the compound-select statement "p". Return NULL if
+** the column has no default collating sequence.
+**
+** The collating sequence for the compound select is taken from the
+** left-most term of the select that has a collating sequence.
+*/
+static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
+ CollSeq *pRet;
+ if( p->pPrior ){
+ pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
+ }else{
+ pRet = 0;
+ }
+ if( pRet==0 ){
+ pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
+ }
+ return pRet;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+/* Forward reference */
+static int multiSelectOrderBy(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The right-most of SELECTs to be coded */
+ SelectDest *pDest /* What to do with query results */
+);
+
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** This routine is called to process a compound query form from
+** two or more separate queries using UNION, UNION ALL, EXCEPT, or
+** INTERSECT
+**
+** "p" points to the right-most of the two queries. the query on the
+** left is p->pPrior. The left query could also be a compound query
+** in which case this routine will be called recursively.
+**
+** The results of the total query are to be written into a destination
+** of type eDest with parameter iParm.
+**
+** Example 1: Consider a three-way compound SQL statement.
+**
+** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
+**
+** This statement is parsed up as follows:
+**
+** SELECT c FROM t3
+** |
+** `-----> SELECT b FROM t2
+** |
+** `------> SELECT a FROM t1
+**
+** The arrows in the diagram above represent the Select.pPrior pointer.
+** So if this routine is called with p equal to the t3 query, then
+** pPrior will be the t2 query. p->op will be TK_UNION in this case.
+**
+** Notice that because of the way SQLite parses compound SELECTs, the
+** individual selects always group from left to right.
+*/
+static int multiSelect(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The right-most of SELECTs to be coded */
+ SelectDest *pDest /* What to do with query results */
+){
+ int rc = SQLITE_OK; /* Success code from a subroutine */
+ Select *pPrior; /* Another SELECT immediately to our left */
+ Vdbe *v; /* Generate code to this VDBE */
+ SelectDest dest; /* Alternative data destination */
+ Select *pDelete = 0; /* Chain of simple selects to delete */
+ sqlite3 *db; /* Database connection */
+
+ /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
+ ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
+ */
+ assert( p && p->pPrior ); /* Calling function guarantees this much */
+ db = pParse->db;
+ pPrior = p->pPrior;
+ assert( pPrior->pRightmost!=pPrior );
+ assert( pPrior->pRightmost==p->pRightmost );
+ if( pPrior->pOrderBy ){
+ sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
+ selectOpName(p->op));
+ rc = 1;
+ goto multi_select_end;
+ }
+ if( pPrior->pLimit ){
+ sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
+ selectOpName(p->op));
+ rc = 1;
+ goto multi_select_end;
+ }
+
+ v = sqlite3GetVdbe(pParse);
+ assert( v!=0 ); /* The VDBE already created by calling function */
+
+ /* Create the destination temporary table if necessary
+ */
+ dest = *pDest;
+ if( dest.eDest==SRT_EphemTab ){
+ assert( p->pEList );
+ sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, p->pEList->nExpr);
+ dest.eDest = SRT_Table;
+ }
+
+ /* Make sure all SELECTs in the statement have the same number of elements
+ ** in their result sets.
+ */
+ assert( p->pEList && pPrior->pEList );
+ if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
+ sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
+ " do not have the same number of result columns", selectOpName(p->op));
+ rc = 1;
+ goto multi_select_end;
+ }
+
+ /* Compound SELECTs that have an ORDER BY clause are handled separately.
+ */
+ if( p->pOrderBy ){
+ return multiSelectOrderBy(pParse, p, pDest);
+ }
+
+ /* Generate code for the left and right SELECT statements.
+ */
+ switch( p->op ){
+ case TK_ALL: {
+ int addr = 0;
+ assert( !pPrior->pLimit );
+ pPrior->pLimit = p->pLimit;
+ pPrior->pOffset = p->pOffset;
+ rc = sqlite3Select(pParse, pPrior, &dest, 0, 0, 0);
+ p->pLimit = 0;
+ p->pOffset = 0;
+ if( rc ){
+ goto multi_select_end;
+ }
+ p->pPrior = 0;
+ p->iLimit = pPrior->iLimit;
+ p->iOffset = pPrior->iOffset;
+ if( p->iLimit ){
+ addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
+ VdbeComment((v, "Jump ahead if LIMIT reached"));
+ }
+ rc = sqlite3Select(pParse, p, &dest, 0, 0, 0);
+ pDelete = p->pPrior;
+ p->pPrior = pPrior;
+ if( rc ){
+ goto multi_select_end;
+ }
+ if( addr ){
+ sqlite3VdbeJumpHere(v, addr);
+ }
+ break;
+ }
+ case TK_EXCEPT:
+ case TK_UNION: {
+ int unionTab; /* Cursor number of the temporary table holding result */
+ int op = 0; /* One of the SRT_ operations to apply to self */
+ int priorOp; /* The SRT_ operation to apply to prior selects */
+ Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
+ int addr;
+ SelectDest uniondest;
+
+ priorOp = SRT_Union;
+ if( dest.eDest==priorOp && !p->pLimit && !p->pOffset ){
+ /* We can reuse a temporary table generated by a SELECT to our
+ ** right.
+ */
+ unionTab = dest.iParm;
+ }else{
+ /* We will need to create our own temporary table to hold the
+ ** intermediate results.
+ */
+ unionTab = pParse->nTab++;
+ assert( p->pOrderBy==0 );
+ addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
+ assert( p->addrOpenEphm[0] == -1 );
+ p->addrOpenEphm[0] = addr;
+ p->pRightmost->usesEphm = 1;
+ assert( p->pEList );
+ }
+
+ /* Code the SELECT statements to our left
+ */
+ assert( !pPrior->pOrderBy );
+ sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
+ rc = sqlite3Select(pParse, pPrior, &uniondest, 0, 0, 0);
+ if( rc ){
+ goto multi_select_end;
+ }
+
+ /* Code the current SELECT statement
+ */
+ if( p->op==TK_EXCEPT ){
+ op = SRT_Except;
+ }else{
+ assert( p->op==TK_UNION );
+ op = SRT_Union;
+ }
+ p->pPrior = 0;
+ p->disallowOrderBy = 0;
+ pLimit = p->pLimit;
+ p->pLimit = 0;
+ pOffset = p->pOffset;
+ p->pOffset = 0;
+ uniondest.eDest = op;
+ rc = sqlite3Select(pParse, p, &uniondest, 0, 0, 0);
+ /* Query flattening in sqlite3Select() might refill p->pOrderBy.
+ ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
+ sqlite3ExprListDelete(db, p->pOrderBy);
+ pDelete = p->pPrior;
+ p->pPrior = pPrior;
+ p->pOrderBy = 0;
+ sqlite3ExprDelete(db, p->pLimit);
+ p->pLimit = pLimit;
+ p->pOffset = pOffset;
+ p->iLimit = 0;
+ p->iOffset = 0;
+ if( rc ){
+ goto multi_select_end;
+ }
+
+
+ /* Convert the data in the temporary table into whatever form
+ ** it is that we currently need.
+ */
+ if( dest.eDest!=priorOp || unionTab!=dest.iParm ){
+ int iCont, iBreak, iStart;
+ assert( p->pEList );
+ if( dest.eDest==SRT_Callback ){
+ Select *pFirst = p;
+ while( pFirst->pPrior ) pFirst = pFirst->pPrior;
+ generateColumnNames(pParse, 0, pFirst->pEList);
+ }
+ iBreak = sqlite3VdbeMakeLabel(v);
+ iCont = sqlite3VdbeMakeLabel(v);
+ computeLimitRegisters(pParse, p, iBreak);
+ sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
+ iStart = sqlite3VdbeCurrentAddr(v);
+ selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
+ 0, -1, &dest, iCont, iBreak);
+ sqlite3VdbeResolveLabel(v, iCont);
+ sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
+ sqlite3VdbeResolveLabel(v, iBreak);
+ sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
+ }
+ break;
+ }
+ case TK_INTERSECT: {
+ int tab1, tab2;
+ int iCont, iBreak, iStart;
+ Expr *pLimit, *pOffset;
+ int addr;
+ SelectDest intersectdest;
+ int r1;
+
+ /* INTERSECT is different from the others since it requires
+ ** two temporary tables. Hence it has its own case. Begin
+ ** by allocating the tables we will need.
+ */
+ tab1 = pParse->nTab++;
+ tab2 = pParse->nTab++;
+ assert( p->pOrderBy==0 );
+
+ addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
+ assert( p->addrOpenEphm[0] == -1 );
+ p->addrOpenEphm[0] = addr;
+ p->pRightmost->usesEphm = 1;
+ assert( p->pEList );
+
+ /* Code the SELECTs to our left into temporary table "tab1".
+ */
+ sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
+ rc = sqlite3Select(pParse, pPrior, &intersectdest, 0, 0, 0);
+ if( rc ){
+ goto multi_select_end;
+ }
+
+ /* Code the current SELECT into temporary table "tab2"
+ */
+ addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
+ assert( p->addrOpenEphm[1] == -1 );
+ p->addrOpenEphm[1] = addr;
+ p->pPrior = 0;
+ pLimit = p->pLimit;
+ p->pLimit = 0;
+ pOffset = p->pOffset;
+ p->pOffset = 0;
+ intersectdest.iParm = tab2;
+ rc = sqlite3Select(pParse, p, &intersectdest, 0, 0, 0);
+ pDelete = p->pPrior;
+ p->pPrior = pPrior;
+ sqlite3ExprDelete(db, p->pLimit);
+ p->pLimit = pLimit;
+ p->pOffset = pOffset;
+ if( rc ){
+ goto multi_select_end;
+ }
+
+ /* Generate code to take the intersection of the two temporary
+ ** tables.
+ */
+ assert( p->pEList );
+ if( dest.eDest==SRT_Callback ){
+ Select *pFirst = p;
+ while( pFirst->pPrior ) pFirst = pFirst->pPrior;
+ generateColumnNames(pParse, 0, pFirst->pEList);
+ }
+ iBreak = sqlite3VdbeMakeLabel(v);
+ iCont = sqlite3VdbeMakeLabel(v);
+ computeLimitRegisters(pParse, p, iBreak);
+ sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
+ r1 = sqlite3GetTempReg(pParse);
+ iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
+ sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
+ sqlite3ReleaseTempReg(pParse, r1);
+ selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
+ 0, -1, &dest, iCont, iBreak);
+ sqlite3VdbeResolveLabel(v, iCont);
+ sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
+ sqlite3VdbeResolveLabel(v, iBreak);
+ sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
+ sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
+ break;
+ }
+ }
+
+ /* Compute collating sequences used by
+ ** temporary tables needed to implement the compound select.
+ ** Attach the KeyInfo structure to all temporary tables.
+ **
+ ** This section is run by the right-most SELECT statement only.
+ ** SELECT statements to the left always skip this part. The right-most
+ ** SELECT might also skip this part if it has no ORDER BY clause and
+ ** no temp tables are required.
+ */
+ if( p->usesEphm ){
+ int i; /* Loop counter */
+ KeyInfo *pKeyInfo; /* Collating sequence for the result set */
+ Select *pLoop; /* For looping through SELECT statements */
+ CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
+ int nCol; /* Number of columns in result set */
+
+ assert( p->pRightmost==p );
+ nCol = p->pEList->nExpr;
+ pKeyInfo = sqlite3DbMallocZero(db,
+ sizeof(*pKeyInfo)+nCol*(sizeof(CollSeq*) + 1));
+ if( !pKeyInfo ){
+ rc = SQLITE_NOMEM;
+ goto multi_select_end;
+ }
+
+ pKeyInfo->enc = ENC(db);
+ pKeyInfo->nField = nCol;
+
+ for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
+ *apColl = multiSelectCollSeq(pParse, p, i);
+ if( 0==*apColl ){
+ *apColl = db->pDfltColl;
+ }
+ }
+
+ for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
+ for(i=0; i<2; i++){
+ int addr = pLoop->addrOpenEphm[i];
+ if( addr<0 ){
+ /* If [0] is unused then [1] is also unused. So we can
+ ** always safely abort as soon as the first unused slot is found */
+ assert( pLoop->addrOpenEphm[1]<0 );
+ break;
+ }
+ sqlite3VdbeChangeP2(v, addr, nCol);
+ sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
+ pLoop->addrOpenEphm[i] = -1;
+ }
+ }
+ sqlite3DbFree(db, pKeyInfo);
+ }
+
+multi_select_end:
+ pDest->iMem = dest.iMem;
+ pDest->nMem = dest.nMem;
+ sqlite3SelectDelete(db, pDelete);
+ return rc;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+/*
+** Code an output subroutine for a coroutine implementation of a
+** SELECT statment.
+**
+** The data to be output is contained in pIn->iMem. There are
+** pIn->nMem columns to be output. pDest is where the output should
+** be sent.
+**
+** regReturn is the number of the register holding the subroutine
+** return address.
+**
+** If regPrev>0 then it is a the first register in a vector that
+** records the previous output. mem[regPrev] is a flag that is false
+** if there has been no previous output. If regPrev>0 then code is
+** generated to suppress duplicates. pKeyInfo is used for comparing
+** keys.
+**
+** If the LIMIT found in p->iLimit is reached, jump immediately to
+** iBreak.
+*/
+static int generateOutputSubroutine(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The SELECT statement */
+ SelectDest *pIn, /* Coroutine supplying data */
+ SelectDest *pDest, /* Where to send the data */
+ int regReturn, /* The return address register */
+ int regPrev, /* Previous result register. No uniqueness if 0 */
+ KeyInfo *pKeyInfo, /* For comparing with previous entry */
+ int p4type, /* The p4 type for pKeyInfo */
+ int iBreak /* Jump here if we hit the LIMIT */
+){
+ Vdbe *v = pParse->pVdbe;
+ int iContinue;
+ int addr;
+
+ addr = sqlite3VdbeCurrentAddr(v);
+ iContinue = sqlite3VdbeMakeLabel(v);
+
+ /* Suppress duplicates for UNION, EXCEPT, and INTERSECT
+ */
+ if( regPrev ){
+ int j1, j2;
+ j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
+ j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
+ (char*)pKeyInfo, p4type);
+ sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
+ sqlite3VdbeJumpHere(v, j1);
+ sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
+ }
+ if( pParse->db->mallocFailed ) return 0;
+
+ /* Suppress the the first OFFSET entries if there is an OFFSET clause
+ */
+ codeOffset(v, p, iContinue);
+
+ switch( pDest->eDest ){
+ /* Store the result as data using a unique key.
+ */
+ case SRT_Table:
+ case SRT_EphemTab: {
+ int r1 = sqlite3GetTempReg(pParse);
+ int r2 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iMem, pIn->nMem, r1);
+ sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iParm, r2);
+ sqlite3VdbeAddOp3(v, OP_Insert, pDest->iParm, r1, r2);
+ sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+ sqlite3ReleaseTempReg(pParse, r2);
+ sqlite3ReleaseTempReg(pParse, r1);
+ break;
+ }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+ /* If we are creating a set for an "expr IN (SELECT ...)" construct,
+ ** then there should be a single item on the stack. Write this
+ ** item into the set table with bogus data.
+ */
+ case SRT_Set: {
+ int r1;
+ assert( pIn->nMem==1 );
+ p->affinity =
+ sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affinity);
+ r1 = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iMem, 1, r1, &p->affinity, 1);
+ sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, 1);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iParm, r1);
+ sqlite3ReleaseTempReg(pParse, r1);
+ break;
+ }
+
+#if 0 /* Never occurs on an ORDER BY query */
+ /* If any row exist in the result set, record that fact and abort.
+ */
+ case SRT_Exists: {
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iParm);
+ /* The LIMIT clause will terminate the loop for us */
+ break;
+ }
+#endif
+
+ /* If this is a scalar select that is part of an expression, then
+ ** store the results in the appropriate memory cell and break out
+ ** of the scan loop.
+ */
+ case SRT_Mem: {
+ assert( pIn->nMem==1 );
+ sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iParm, 1);
+ /* The LIMIT clause will jump out of the loop for us */
+ break;
+ }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+ /* Send the data to the callback function or to a subroutine. In the
+ ** case of a subroutine, the subroutine itself is responsible for
+ ** popping the data from the stack.
+ */
+ case SRT_Coroutine: {
+ if( pDest->iMem==0 ){
+ pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
+ pDest->nMem = pIn->nMem;
+ }
+ sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
+ sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
+ break;
+ }
+
+ case SRT_Callback: {
+ sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
+ sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);
+ break;
+ }
+
+#if !defined(SQLITE_OMIT_TRIGGER)
+ /* Discard the results. This is used for SELECT statements inside
+ ** the body of a TRIGGER. The purpose of such selects is to call
+ ** user-defined functions that have side effects. We do not care
+ ** about the actual results of the select.
+ */
+ default: {
+ break;
+ }
+#endif
+ }
+
+ /* Jump to the end of the loop if the LIMIT is reached.
+ */
+ if( p->iLimit ){
+ sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+ sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+ }
+
+ /* Generate the subroutine return
+ */
+ sqlite3VdbeResolveLabel(v, iContinue);
+ sqlite3VdbeAddOp1(v, OP_Return, regReturn);
+
+ return addr;
+}
+
+/*
+** Alternative compound select code generator for cases when there
+** is an ORDER BY clause.
+**
+** We assume a query of the following form:
+**
+** <selectA> <operator> <selectB> ORDER BY <orderbylist>
+**
+** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT. The idea
+** is to code both <selectA> and <selectB> with the ORDER BY clause as
+** co-routines. Then run the co-routines in parallel and merge the results
+** into the output. In addition to the two coroutines (called selectA and
+** selectB) there are 7 subroutines:
+**
+** outA: Move the output of the selectA coroutine into the output
+** of the compound query.
+**
+** outB: Move the output of the selectB coroutine into the output
+** of the compound query. (Only generated for UNION and
+** UNION ALL. EXCEPT and INSERTSECT never output a row that
+** appears only in B.)
+**
+** AltB: Called when there is data from both coroutines and A<B.
+**
+** AeqB: Called when there is data from both coroutines and A==B.
+**
+** AgtB: Called when there is data from both coroutines and A>B.
+**
+** EofA: Called when data is exhausted from selectA.
+**
+** EofB: Called when data is exhausted from selectB.
+**
+** The implementation of the latter five subroutines depend on which
+** <operator> is used:
+**
+**
+** UNION ALL UNION EXCEPT INTERSECT
+** ------------- ----------------- -------------- -----------------
+** AltB: outA, nextA outA, nextA outA, nextA nextA
+**
+** AeqB: outA, nextA nextA nextA outA, nextA
+**
+** AgtB: outB, nextB outB, nextB nextB nextB
+**
+** EofA: outB, nextB outB, nextB halt halt
+**
+** EofB: outA, nextA outA, nextA outA, nextA halt
+**
+** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
+** causes an immediate jump to EofA and an EOF on B following nextB causes
+** an immediate jump to EofB. Within EofA and EofB, and EOF on entry or
+** following nextX causes a jump to the end of the select processing.
+**
+** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
+** within the output subroutine. The regPrev register set holds the previously
+** output value. A comparison is made against this value and the output
+** is skipped if the next results would be the same as the previous.
+**
+** The implementation plan is to implement the two coroutines and seven
+** subroutines first, then put the control logic at the bottom. Like this:
+**
+** goto Init
+** coA: coroutine for left query (A)
+** coB: coroutine for right query (B)
+** outA: output one row of A
+** outB: output one row of B (UNION and UNION ALL only)
+** EofA: ...
+** EofB: ...
+** AltB: ...
+** AeqB: ...
+** AgtB: ...
+** Init: initialize coroutine registers
+** yield coA
+** if eof(A) goto EofA
+** yield coB
+** if eof(B) goto EofB
+** Cmpr: Compare A, B
+** Jump AltB, AeqB, AgtB
+** End: ...
+**
+** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
+** actually called using Gosub and they do not Return. EofA and EofB loop
+** until all data is exhausted then jump to the "end" labe. AltB, AeqB,
+** and AgtB jump to either L2 or to one of EofA or EofB.
+*/
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+static int multiSelectOrderBy(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The right-most of SELECTs to be coded */
+ SelectDest *pDest /* What to do with query results */
+){
+ int i, j; /* Loop counters */
+ Select *pPrior; /* Another SELECT immediately to our left */
+ Vdbe *v; /* Generate code to this VDBE */
+ SelectDest destA; /* Destination for coroutine A */
+ SelectDest destB; /* Destination for coroutine B */
+ int regAddrA; /* Address register for select-A coroutine */
+ int regEofA; /* Flag to indicate when select-A is complete */
+ int regAddrB; /* Address register for select-B coroutine */
+ int regEofB; /* Flag to indicate when select-B is complete */
+ int addrSelectA; /* Address of the select-A coroutine */
+ int addrSelectB; /* Address of the select-B coroutine */
+ int regOutA; /* Address register for the output-A subroutine */
+ int regOutB; /* Address register for the output-B subroutine */
+ int addrOutA; /* Address of the output-A subroutine */
+ int addrOutB; /* Address of the output-B subroutine */
+ int addrEofA; /* Address of the select-A-exhausted subroutine */
+ int addrEofB; /* Address of the select-B-exhausted subroutine */
+ int addrAltB; /* Address of the A<B subroutine */
+ int addrAeqB; /* Address of the A==B subroutine */
+ int addrAgtB; /* Address of the A>B subroutine */
+ int regLimitA; /* Limit register for select-A */
+ int regLimitB; /* Limit register for select-A */
+ int regPrev; /* A range of registers to hold previous output */
+ int savedLimit; /* Saved value of p->iLimit */
+ int savedOffset; /* Saved value of p->iOffset */
+ int labelCmpr; /* Label for the start of the merge algorithm */
+ int labelEnd; /* Label for the end of the overall SELECT stmt */
+ int j1; /* Jump instructions that get retargetted */
+ int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
+ KeyInfo *pKeyDup; /* Comparison information for duplicate removal */
+ KeyInfo *pKeyMerge; /* Comparison information for merging rows */
+ sqlite3 *db; /* Database connection */
+ ExprList *pOrderBy; /* The ORDER BY clause */
+ int nOrderBy; /* Number of terms in the ORDER BY clause */
+ int *aPermute; /* Mapping from ORDER BY terms to result set columns */
+ u8 NotUsed; /* Dummy variables */
+
+ assert( p->pOrderBy!=0 );
+ db = pParse->db;
+ v = pParse->pVdbe;
+ if( v==0 ) return SQLITE_NOMEM;
+ labelEnd = sqlite3VdbeMakeLabel(v);
+ labelCmpr = sqlite3VdbeMakeLabel(v);
+
+
+ /* Patch up the ORDER BY clause
+ */
+ op = p->op;
+ pPrior = p->pPrior;
+ assert( pPrior->pOrderBy==0 );
+ pOrderBy = p->pOrderBy;
+ assert( pOrderBy );
+ if( processCompoundOrderBy(pParse, p) ){
+ return SQLITE_ERROR;
+ }
+ nOrderBy = pOrderBy->nExpr;
+
+ /* For operators other than UNION ALL we have to make sure that
+ ** the ORDER BY clause covers every term of the result set. Add
+ ** terms to the ORDER BY clause as necessary.
+ */
+ if( op!=TK_ALL ){
+ for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
+ for(j=0; j<nOrderBy; j++){
+ Expr *pTerm = pOrderBy->a[j].pExpr;
+ assert( pTerm->op==TK_INTEGER );
+ assert( (pTerm->flags & EP_IntValue)!=0 );
+ if( pTerm->iTable==i ) break;
+ }
+ if( j==nOrderBy ){
+ Expr *pNew = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, 0);
+ if( pNew==0 ) return SQLITE_NOMEM;
+ pNew->flags |= EP_IntValue;
+ pNew->iTable = i;
+ pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew, 0);
+ nOrderBy++;
+ }
+ }
+ }
+
+ /* Compute the comparison permutation and keyinfo that is used with
+ ** the permutation in order to comparisons to determine if the next
+ ** row of results comes from selectA or selectB. Also add explicit
+ ** collations to the ORDER BY clause terms so that when the subqueries
+ ** to the right and the left are evaluated, they use the correct
+ ** collation.
+ */
+ aPermute = sqlite3DbMallocRaw(db, sizeof(int)*nOrderBy);
+ if( aPermute ){
+ for(i=0; i<nOrderBy; i++){
+ Expr *pTerm = pOrderBy->a[i].pExpr;
+ assert( pTerm->op==TK_INTEGER );
+ assert( (pTerm->flags & EP_IntValue)!=0 );
+ aPermute[i] = pTerm->iTable-1;
+ assert( aPermute[i]>=0 && aPermute[i]<p->pEList->nExpr );
+ }
+ pKeyMerge =
+ sqlite3DbMallocRaw(db, sizeof(*pKeyMerge)+nOrderBy*(sizeof(CollSeq*)+1));
+ if( pKeyMerge ){
+ pKeyMerge->aSortOrder = (u8*)&pKeyMerge->aColl[nOrderBy];
+ pKeyMerge->nField = nOrderBy;
+ pKeyMerge->enc = ENC(db);
+ for(i=0; i<nOrderBy; i++){
+ CollSeq *pColl;
+ Expr *pTerm = pOrderBy->a[i].pExpr;
+ if( pTerm->flags & EP_ExpCollate ){
+ pColl = pTerm->pColl;
+ }else{
+ pColl = multiSelectCollSeq(pParse, p, aPermute[i]);
+ pTerm->flags |= EP_ExpCollate;
+ pTerm->pColl = pColl;
+ }
+ pKeyMerge->aColl[i] = pColl;
+ pKeyMerge->aSortOrder[i] = pOrderBy->a[i].sortOrder;
+ }
+ }
+ }else{
+ pKeyMerge = 0;
+ }
+
+ /* Reattach the ORDER BY clause to the query.
+ */
+ p->pOrderBy = pOrderBy;
+ pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy);
+
+ /* Allocate a range of temporary registers and the KeyInfo needed
+ ** for the logic that removes duplicate result rows when the
+ ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
+ */
+ if( op==TK_ALL ){
+ regPrev = 0;
+ }else{
+ int nExpr = p->pEList->nExpr;
+ assert( nOrderBy>=nExpr );
+ regPrev = sqlite3GetTempRange(pParse, nExpr+1);
+ sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
+ pKeyDup = sqlite3DbMallocZero(db,
+ sizeof(*pKeyDup) + nExpr*(sizeof(CollSeq*)+1) );
+ if( pKeyDup ){
+ pKeyDup->aSortOrder = (u8*)&pKeyDup->aColl[nExpr];
+ pKeyDup->nField = nExpr;
+ pKeyDup->enc = ENC(db);
+ for(i=0; i<nExpr; i++){
+ pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
+ pKeyDup->aSortOrder[i] = 0;
+ }
+ }
+ }
+
+ /* Separate the left and the right query from one another
+ */
+ p->pPrior = 0;
+ pPrior->pRightmost = 0;
+ processOrderGroupBy(pParse, p, p->pOrderBy, 1, &NotUsed);
+ if( pPrior->pPrior==0 ){
+ processOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, 1, &NotUsed);
+ }
+
+ /* Compute the limit registers */
+ computeLimitRegisters(pParse, p, labelEnd);
+ if( p->iLimit && op==TK_ALL ){
+ regLimitA = ++pParse->nMem;
+ regLimitB = ++pParse->nMem;
+ sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
+ regLimitA);
+ sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
+ }else{
+ regLimitA = regLimitB = 0;
+ }
+ sqlite3ExprDelete(db, p->pLimit);
+ p->pLimit = 0;
+ sqlite3ExprDelete(db, p->pOffset);
+ p->pOffset = 0;
+
+ regAddrA = ++pParse->nMem;
+ regEofA = ++pParse->nMem;
+ regAddrB = ++pParse->nMem;
+ regEofB = ++pParse->nMem;
+ regOutA = ++pParse->nMem;
+ regOutB = ++pParse->nMem;
+ sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
+ sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
+
+ /* Jump past the various subroutines and coroutines to the main
+ ** merge loop
+ */
+ j1 = sqlite3VdbeAddOp0(v, OP_Goto);
+ addrSelectA = sqlite3VdbeCurrentAddr(v);
+
+
+ /* Generate a coroutine to evaluate the SELECT statement to the
+ ** left of the compound operator - the "A" select.
+ */
+ VdbeNoopComment((v, "Begin coroutine for left SELECT"));
+ pPrior->iLimit = regLimitA;
+ sqlite3Select(pParse, pPrior, &destA, 0, 0, 0);
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
+ VdbeNoopComment((v, "End coroutine for left SELECT"));
+
+ /* Generate a coroutine to evaluate the SELECT statement on
+ ** the right - the "B" select
+ */
+ addrSelectB = sqlite3VdbeCurrentAddr(v);
+ VdbeNoopComment((v, "Begin coroutine for right SELECT"));
+ savedLimit = p->iLimit;
+ savedOffset = p->iOffset;
+ p->iLimit = regLimitB;
+ p->iOffset = 0;
+ sqlite3Select(pParse, p, &destB, 0, 0, 0);
+ p->iLimit = savedLimit;
+ p->iOffset = savedOffset;
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
+ VdbeNoopComment((v, "End coroutine for right SELECT"));
+
+ /* Generate a subroutine that outputs the current row of the A
+ ** select as the next output row of the compound select.
+ */
+ VdbeNoopComment((v, "Output routine for A"));
+ addrOutA = generateOutputSubroutine(pParse,
+ p, &destA, pDest, regOutA,
+ regPrev, pKeyDup, P4_KEYINFO_HANDOFF, labelEnd);
+
+ /* Generate a subroutine that outputs the current row of the B
+ ** select as the next output row of the compound select.
+ */
+ if( op==TK_ALL || op==TK_UNION ){
+ VdbeNoopComment((v, "Output routine for B"));
+ addrOutB = generateOutputSubroutine(pParse,
+ p, &destB, pDest, regOutB,
+ regPrev, pKeyDup, P4_KEYINFO_STATIC, labelEnd);
+ }
+
+ /* Generate a subroutine to run when the results from select A
+ ** are exhausted and only data in select B remains.
+ */
+ VdbeNoopComment((v, "eof-A subroutine"));
+ if( op==TK_EXCEPT || op==TK_INTERSECT ){
+ addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
+ }else{
+ addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
+ sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
+ }
+
+ /* Generate a subroutine to run when the results from select B
+ ** are exhausted and only data in select A remains.
+ */
+ if( op==TK_INTERSECT ){
+ addrEofB = addrEofA;
+ }else{
+ VdbeNoopComment((v, "eof-B subroutine"));
+ addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
+ sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
+ }
+
+ /* Generate code to handle the case of A<B
+ */
+ VdbeNoopComment((v, "A-lt-B subroutine"));
+ addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
+ sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
+
+ /* Generate code to handle the case of A==B
+ */
+ if( op==TK_ALL ){
+ addrAeqB = addrAltB;
+ }else if( op==TK_INTERSECT ){
+ addrAeqB = addrAltB;
+ addrAltB++;
+ }else{
+ VdbeNoopComment((v, "A-eq-B subroutine"));
+ addrAeqB =
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
+ sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
+ }
+
+ /* Generate code to handle the case of A>B
+ */
+ VdbeNoopComment((v, "A-gt-B subroutine"));
+ addrAgtB = sqlite3VdbeCurrentAddr(v);
+ if( op==TK_ALL || op==TK_UNION ){
+ sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
+ }
+ sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
+ sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
+
+ /* This code runs once to initialize everything.
+ */
+ sqlite3VdbeJumpHere(v, j1);
+ sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
+ sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
+ sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);
+ sqlite3VdbeAddOp2(v, OP_Gosub, regAddrB, addrSelectB);
+ sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
+ sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
+
+ /* Implement the main merge loop
+ */
+ sqlite3VdbeResolveLabel(v, labelCmpr);
+ sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
+ sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, nOrderBy,
+ (char*)pKeyMerge, P4_KEYINFO_HANDOFF);
+ sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);
+
+ /* Release temporary registers
+ */
+ if( regPrev ){
+ sqlite3ReleaseTempRange(pParse, regPrev, nOrderBy+1);
+ }
+
+ /* Jump to the this point in order to terminate the query.
+ */
+ sqlite3VdbeResolveLabel(v, labelEnd);
+
+ /* Set the number of output columns
+ */
+ if( pDest->eDest==SRT_Callback ){
+ Select *pFirst = pPrior;
+ while( pFirst->pPrior ) pFirst = pFirst->pPrior;
+ generateColumnNames(pParse, 0, pFirst->pEList);
+ }
+
+ /* Reassembly the compound query so that it will be freed correctly
+ ** by the calling function */
+ if( p->pPrior ){
+ sqlite3SelectDelete(db, p->pPrior);
+ }
+ p->pPrior = pPrior;
+
+ /*** TBD: Insert subroutine calls to close cursors on incomplete
+ **** subqueries ****/
+ return SQLITE_OK;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/* Forward Declarations */
+static void substExprList(sqlite3*, ExprList*, int, ExprList*);
+static void substSelect(sqlite3*, Select *, int, ExprList *);
+
+/*
+** Scan through the expression pExpr. Replace every reference to
+** a column in table number iTable with a copy of the iColumn-th
+** entry in pEList. (But leave references to the ROWID column
+** unchanged.)
+**
+** This routine is part of the flattening procedure. A subquery
+** whose result set is defined by pEList appears as entry in the
+** FROM clause of a SELECT such that the VDBE cursor assigned to that
+** FORM clause entry is iTable. This routine make the necessary
+** changes to pExpr so that it refers directly to the source table
+** of the subquery rather the result set of the subquery.
+*/
+static void substExpr(
+ sqlite3 *db, /* Report malloc errors to this connection */
+ Expr *pExpr, /* Expr in which substitution occurs */
+ int iTable, /* Table to be substituted */
+ ExprList *pEList /* Substitute expressions */
+){
+ if( pExpr==0 ) return;
+ if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
+ if( pExpr->iColumn<0 ){
+ pExpr->op = TK_NULL;
+ }else{
+ Expr *pNew;
+ assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
+ assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
+ pNew = pEList->a[pExpr->iColumn].pExpr;
+ assert( pNew!=0 );
+ pExpr->op = pNew->op;
+ assert( pExpr->pLeft==0 );
+ pExpr->pLeft = sqlite3ExprDup(db, pNew->pLeft);
+ assert( pExpr->pRight==0 );
+ pExpr->pRight = sqlite3ExprDup(db, pNew->pRight);
+ assert( pExpr->pList==0 );
+ pExpr->pList = sqlite3ExprListDup(db, pNew->pList);
+ pExpr->iTable = pNew->iTable;
+ pExpr->pTab = pNew->pTab;
+ pExpr->iColumn = pNew->iColumn;
+ pExpr->iAgg = pNew->iAgg;
+ sqlite3TokenCopy(db, &pExpr->token, &pNew->token);
+ sqlite3TokenCopy(db, &pExpr->span, &pNew->span);
+ pExpr->pSelect = sqlite3SelectDup(db, pNew->pSelect);
+ pExpr->flags = pNew->flags;
+ }
+ }else{
+ substExpr(db, pExpr->pLeft, iTable, pEList);
+ substExpr(db, pExpr->pRight, iTable, pEList);
+ substSelect(db, pExpr->pSelect, iTable, pEList);
+ substExprList(db, pExpr->pList, iTable, pEList);
+ }
+}
+static void substExprList(
+ sqlite3 *db, /* Report malloc errors here */
+ ExprList *pList, /* List to scan and in which to make substitutes */
+ int iTable, /* Table to be substituted */
+ ExprList *pEList /* Substitute values */
+){
+ int i;
+ if( pList==0 ) return;
+ for(i=0; i<pList->nExpr; i++){
+ substExpr(db, pList->a[i].pExpr, iTable, pEList);
+ }
+}
+static void substSelect(
+ sqlite3 *db, /* Report malloc errors here */
+ Select *p, /* SELECT statement in which to make substitutions */
+ int iTable, /* Table to be replaced */
+ ExprList *pEList /* Substitute values */
+){
+ if( !p ) return;
+ substExprList(db, p->pEList, iTable, pEList);
+ substExprList(db, p->pGroupBy, iTable, pEList);
+ substExprList(db, p->pOrderBy, iTable, pEList);
+ substExpr(db, p->pHaving, iTable, pEList);
+ substExpr(db, p->pWhere, iTable, pEList);
+ substSelect(db, p->pPrior, iTable, pEList);
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** This routine attempts to flatten subqueries in order to speed
+** execution. It returns 1 if it makes changes and 0 if no flattening
+** occurs.
+**
+** To understand the concept of flattening, consider the following
+** query:
+**
+** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
+**
+** The default way of implementing this query is to execute the
+** subquery first and store the results in a temporary table, then
+** run the outer query on that temporary table. This requires two
+** passes over the data. Furthermore, because the temporary table
+** has no indices, the WHERE clause on the outer query cannot be
+** optimized.
+**
+** This routine attempts to rewrite queries such as the above into
+** a single flat select, like this:
+**
+** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
+**
+** The code generated for this simpification gives the same result
+** but only has to scan the data once. And because indices might
+** exist on the table t1, a complete scan of the data might be
+** avoided.
+**
+** Flattening is only attempted if all of the following are true:
+**
+** (1) The subquery and the outer query do not both use aggregates.
+**
+** (2) The subquery is not an aggregate or the outer query is not a join.
+**
+** (3) The subquery is not the right operand of a left outer join, or
+** the subquery is not itself a join. (Ticket #306)
+**
+** (4) The subquery is not DISTINCT or the outer query is not a join.
+**
+** (5) The subquery is not DISTINCT or the outer query does not use
+** aggregates.
+**
+** (6) The subquery does not use aggregates or the outer query is not
+** DISTINCT.
+**
+** (7) The subquery has a FROM clause.
+**
+** (8) The subquery does not use LIMIT or the outer query is not a join.
+**
+** (9) The subquery does not use LIMIT or the outer query does not use
+** aggregates.
+**
+** (10) The subquery does not use aggregates or the outer query does not
+** use LIMIT.
+**
+** (11) The subquery and the outer query do not both have ORDER BY clauses.
+**
+** (12) The subquery is not the right term of a LEFT OUTER JOIN or the
+** subquery has no WHERE clause. (added by ticket #350)
+**
+** (13) The subquery and outer query do not both use LIMIT
+**
+** (14) The subquery does not use OFFSET
+**
+** (15) The outer query is not part of a compound select or the
+** subquery does not have both an ORDER BY and a LIMIT clause.
+** (See ticket #2339)
+**
+** (16) The outer query is not an aggregate or the subquery does
+** not contain ORDER BY. (Ticket #2942) This used to not matter
+** until we introduced the group_concat() function.
+**
+** (17) The sub-query is not a compound select, or it is a UNION ALL
+** compound clause made up entirely of non-aggregate queries, and
+** the parent query:
+**
+** * is not itself part of a compound select,
+** * is not an aggregate or DISTINCT query, and
+** * has no other tables or sub-selects in the FROM clause.
+**
+** The parent and sub-query may contain WHERE clauses. Subject to
+** rules (11), (13) and (14), they may also contain ORDER BY,
+** LIMIT and OFFSET clauses.
+**
+** (18) If the sub-query is a compound select, then all terms of the
+** ORDER by clause of the parent must be simple references to
+** columns of the sub-query.
+**
+** In this routine, the "p" parameter is a pointer to the outer query.
+** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
+** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
+**
+** If flattening is not attempted, this routine is a no-op and returns 0.
+** If flattening is attempted this routine returns 1.
+**
+** All of the expression analysis must occur on both the outer query and
+** the subquery before this routine runs.
+*/
+static int flattenSubquery(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The parent or outer SELECT statement */
+ int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
+ int isAgg, /* True if outer SELECT uses aggregate functions */
+ int subqueryIsAgg /* True if the subquery uses aggregate functions */
+){
+ const char *zSavedAuthContext = pParse->zAuthContext;
+ Select *pParent;
+ Select *pSub; /* The inner query or "subquery" */
+ Select *pSub1; /* Pointer to the rightmost select in sub-query */
+ SrcList *pSrc; /* The FROM clause of the outer query */
+ SrcList *pSubSrc; /* The FROM clause of the subquery */
+ ExprList *pList; /* The result set of the outer query */
+ int iParent; /* VDBE cursor number of the pSub result set temp table */
+ int i; /* Loop counter */
+ Expr *pWhere; /* The WHERE clause */
+ struct SrcList_item *pSubitem; /* The subquery */
+ sqlite3 *db = pParse->db;
+
+ /* Check to see if flattening is permitted. Return 0 if not.
+ */
+ if( p==0 ) return 0;
+ pSrc = p->pSrc;
+ assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
+ pSubitem = &pSrc->a[iFrom];
+ iParent = pSubitem->iCursor;
+ pSub = pSubitem->pSelect;
+ assert( pSub!=0 );
+ if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
+ if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
+ pSubSrc = pSub->pSrc;
+ assert( pSubSrc );
+ /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
+ ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
+ ** because they could be computed at compile-time. But when LIMIT and OFFSET
+ ** became arbitrary expressions, we were forced to add restrictions (13)
+ ** and (14). */
+ if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */
+ if( pSub->pOffset ) return 0; /* Restriction (14) */
+ if( p->pRightmost && pSub->pLimit && pSub->pOrderBy ){
+ return 0; /* Restriction (15) */
+ }
+ if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */
+ if( (pSub->isDistinct || pSub->pLimit)
+ && (pSrc->nSrc>1 || isAgg) ){ /* Restrictions (4)(5)(8)(9) */
+ return 0;
+ }
+ if( p->isDistinct && subqueryIsAgg ) return 0; /* Restriction (6) */
+ if( (p->disallowOrderBy || p->pOrderBy) && pSub->pOrderBy ){
+ return 0; /* Restriction (11) */
+ }
+ if( isAgg && pSub->pOrderBy ) return 0; /* Restriction (16) */
+
+ /* Restriction 3: If the subquery is a join, make sure the subquery is
+ ** not used as the right operand of an outer join. Examples of why this
+ ** is not allowed:
+ **
+ ** t1 LEFT OUTER JOIN (t2 JOIN t3)
+ **
+ ** If we flatten the above, we would get
+ **
+ ** (t1 LEFT OUTER JOIN t2) JOIN t3
+ **
+ ** which is not at all the same thing.
+ */
+ if( pSubSrc->nSrc>1 && (pSubitem->jointype & JT_OUTER)!=0 ){
+ return 0;
+ }
+
+ /* Restriction 12: If the subquery is the right operand of a left outer
+ ** join, make sure the subquery has no WHERE clause.
+ ** An examples of why this is not allowed:
+ **
+ ** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
+ **
+ ** If we flatten the above, we would get
+ **
+ ** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
+ **
+ ** But the t2.x>0 test will always fail on a NULL row of t2, which
+ ** effectively converts the OUTER JOIN into an INNER JOIN.
+ */
+ if( (pSubitem->jointype & JT_OUTER)!=0 && pSub->pWhere!=0 ){
+ return 0;
+ }
+
+ /* Restriction 17: If the sub-query is a compound SELECT, then it must
+ ** use only the UNION ALL operator. And none of the simple select queries
+ ** that make up the compound SELECT are allowed to be aggregate or distinct
+ ** queries.
+ */
+ if( pSub->pPrior ){
+ if( p->pPrior || isAgg || p->isDistinct || pSrc->nSrc!=1 ){
+ return 0;
+ }
+ for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
+ if( pSub1->isAgg || pSub1->isDistinct
+ || (pSub1->pPrior && pSub1->op!=TK_ALL)
+ || !pSub1->pSrc || pSub1->pSrc->nSrc!=1
+ ){
+ return 0;
+ }
+ }
+
+ /* Restriction 18. */
+ if( p->pOrderBy ){
+ int ii;
+ for(ii=0; ii<p->pOrderBy->nExpr; ii++){
+ Expr *pExpr = p->pOrderBy->a[ii].pExpr;
+ if( pExpr->op!=TK_COLUMN || pExpr->iTable!=iParent ){
+ return 0;
+ }
+ }
+ }
+ }
+
+ pParse->zAuthContext = pSubitem->zName;
+ sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
+ pParse->zAuthContext = zSavedAuthContext;
+
+ /* If the sub-query is a compound SELECT statement, then it must be
+ ** a UNION ALL and the parent query must be of the form:
+ **
+ ** SELECT <expr-list> FROM (<sub-query>) <where-clause>
+ **
+ ** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block
+ ** creates N copies of the parent query without any ORDER BY, LIMIT or
+ ** OFFSET clauses and joins them to the left-hand-side of the original
+ ** using UNION ALL operators. In this case N is the number of simple
+ ** select statements in the compound sub-query.
+ */
+ for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
+ Select *pNew;
+ ExprList *pOrderBy = p->pOrderBy;
+ Expr *pLimit = p->pLimit;
+ Expr *pOffset = p->pOffset;
+ Select *pPrior = p->pPrior;
+ p->pOrderBy = 0;
+ p->pSrc = 0;
+ p->pPrior = 0;
+ p->pLimit = 0;
+ pNew = sqlite3SelectDup(db, p);
+ pNew->pPrior = pPrior;
+ p->pPrior = pNew;
+ p->pOrderBy = pOrderBy;
+ p->op = TK_ALL;
+ p->pSrc = pSrc;
+ p->pLimit = pLimit;
+ p->pOffset = pOffset;
+ p->pRightmost = 0;
+ pNew->pRightmost = 0;
+ }
+
+ /* If we reach this point, it means flattening is permitted for the
+ ** iFrom-th entry of the FROM clause in the outer query.
+ */
+ pSub = pSub1 = pSubitem->pSelect;
+ for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
+ int nSubSrc = pSubSrc->nSrc;
+ int jointype = 0;
+ pSubSrc = pSub->pSrc;
+ pSrc = pParent->pSrc;
+
+ /* Move all of the FROM elements of the subquery into the
+ ** the FROM clause of the outer query. Before doing this, remember
+ ** the cursor number for the original outer query FROM element in
+ ** iParent. The iParent cursor will never be used. Subsequent code
+ ** will scan expressions looking for iParent references and replace
+ ** those references with expressions that resolve to the subquery FROM
+ ** elements we are now copying in.
+ */
+ if( pSrc ){
+ pSubitem = &pSrc->a[iFrom];
+ nSubSrc = pSubSrc->nSrc;
+ jointype = pSubitem->jointype;
+ sqlite3DeleteTable(pSubitem->pTab);
+ sqlite3DbFree(db, pSubitem->zDatabase);
+ sqlite3DbFree(db, pSubitem->zName);
+ sqlite3DbFree(db, pSubitem->zAlias);
+ pSubitem->pTab = 0;
+ pSubitem->zDatabase = 0;
+ pSubitem->zName = 0;
+ pSubitem->zAlias = 0;
+ }
+ if( nSubSrc!=1 || !pSrc ){
+ int extra = nSubSrc - 1;
+ for(i=(pSrc?1:0); i<nSubSrc; i++){
+ pSrc = sqlite3SrcListAppend(db, pSrc, 0, 0);
+ if( pSrc==0 ){
+ pParent->pSrc = 0;
+ return 1;
+ }
+ }
+ pParent->pSrc = pSrc;
+ for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
+ pSrc->a[i] = pSrc->a[i-extra];
+ }
+ }
+ for(i=0; i<nSubSrc; i++){
+ pSrc->a[i+iFrom] = pSubSrc->a[i];
+ memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
+ }
+ pSrc->a[iFrom].jointype = jointype;
+
+ /* Now begin substituting subquery result set expressions for
+ ** references to the iParent in the outer query.
+ **
+ ** Example:
+ **
+ ** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
+ ** \ \_____________ subquery __________/ /
+ ** \_____________________ outer query ______________________________/
+ **
+ ** We look at every expression in the outer query and every place we see
+ ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
+ */
+ pList = pParent->pEList;
+ for(i=0; i<pList->nExpr; i++){
+ Expr *pExpr;
+ if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
+ pList->a[i].zName =
+ sqlite3DbStrNDup(db, (char*)pExpr->span.z, pExpr->span.n);
+ }
+ }
+ substExprList(db, pParent->pEList, iParent, pSub->pEList);
+ if( isAgg ){
+ substExprList(db, pParent->pGroupBy, iParent, pSub->pEList);
+ substExpr(db, pParent->pHaving, iParent, pSub->pEList);
+ }
+ if( pSub->pOrderBy ){
+ assert( pParent->pOrderBy==0 );
+ pParent->pOrderBy = pSub->pOrderBy;
+ pSub->pOrderBy = 0;
+ }else if( pParent->pOrderBy ){
+ substExprList(db, pParent->pOrderBy, iParent, pSub->pEList);
+ }
+ if( pSub->pWhere ){
+ pWhere = sqlite3ExprDup(db, pSub->pWhere);
+ }else{
+ pWhere = 0;
+ }
+ if( subqueryIsAgg ){
+ assert( pParent->pHaving==0 );
+ pParent->pHaving = pParent->pWhere;
+ pParent->pWhere = pWhere;
+ substExpr(db, pParent->pHaving, iParent, pSub->pEList);
+ pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving,
+ sqlite3ExprDup(db, pSub->pHaving));
+ assert( pParent->pGroupBy==0 );
+ pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy);
+ }else{
+ substExpr(db, pParent->pWhere, iParent, pSub->pEList);
+ pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere);
+ }
+
+ /* The flattened query is distinct if either the inner or the
+ ** outer query is distinct.
+ */
+ pParent->isDistinct = pParent->isDistinct || pSub->isDistinct;
+
+ /*
+ ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
+ **
+ ** One is tempted to try to add a and b to combine the limits. But this
+ ** does not work if either limit is negative.
+ */
+ if( pSub->pLimit ){
+ pParent->pLimit = pSub->pLimit;
+ pSub->pLimit = 0;
+ }
+ }
+
+ /* Finially, delete what is left of the subquery and return
+ ** success.
+ */
+ sqlite3SelectDelete(db, pSub1);
+
+ return 1;
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** Analyze the SELECT statement passed as an argument to see if it
+** is a min() or max() query. Return WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX if
+** it is, or 0 otherwise. At present, a query is considered to be
+** a min()/max() query if:
+**
+** 1. There is a single object in the FROM clause.
+**
+** 2. There is a single expression in the result set, and it is
+** either min(x) or max(x), where x is a column reference.
+*/
+static int minMaxQuery(Parse *pParse, Select *p){
+ Expr *pExpr;
+ ExprList *pEList = p->pEList;
+
+ if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
+ pExpr = pEList->a[0].pExpr;
+ pEList = pExpr->pList;
+ if( pExpr->op!=TK_AGG_FUNCTION || pEList==0 || pEList->nExpr!=1 ) return 0;
+ if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
+ if( pExpr->token.n!=3 ) return WHERE_ORDERBY_NORMAL;
+ if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
+ return WHERE_ORDERBY_MIN;
+ }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
+ return WHERE_ORDERBY_MAX;
+ }
+ return WHERE_ORDERBY_NORMAL;
+}
+
+/*
+** This routine resolves any names used in the result set of the
+** supplied SELECT statement. If the SELECT statement being resolved
+** is a sub-select, then pOuterNC is a pointer to the NameContext
+** of the parent SELECT.
+*/
+int sqlite3SelectResolve(
+ Parse *pParse, /* The parser context */
+ Select *p, /* The SELECT statement being coded. */
+ NameContext *pOuterNC /* The outer name context. May be NULL. */
+){
+ ExprList *pEList; /* Result set. */
+ int i; /* For-loop variable used in multiple places */
+ NameContext sNC; /* Local name-context */
+ ExprList *pGroupBy; /* The group by clause */
+
+ /* If this routine has run before, return immediately. */
+ if( p->isResolved ){
+ assert( !pOuterNC );
+ return SQLITE_OK;
+ }
+ p->isResolved = 1;
+
+ /* If there have already been errors, do nothing. */
+ if( pParse->nErr>0 ){
+ return SQLITE_ERROR;
+ }
+
+ /* Prepare the select statement. This call will allocate all cursors
+ ** required to handle the tables and subqueries in the FROM clause.
+ */
+ if( prepSelectStmt(pParse, p) ){
+ return SQLITE_ERROR;
+ }
+
+ /* Resolve the expressions in the LIMIT and OFFSET clauses. These
+ ** are not allowed to refer to any names, so pass an empty NameContext.
+ */
+ memset(&sNC, 0, sizeof(sNC));
+ sNC.pParse = pParse;
+ if( sqlite3ExprResolveNames(&sNC, p->pLimit) ||
+ sqlite3ExprResolveNames(&sNC, p->pOffset) ){
+ return SQLITE_ERROR;
+ }
+
+ /* Set up the local name-context to pass to ExprResolveNames() to
+ ** resolve the expression-list.
+ */
+ sNC.allowAgg = 1;
+ sNC.pSrcList = p->pSrc;
+ sNC.pNext = pOuterNC;
+
+ /* Resolve names in the result set. */
+ pEList = p->pEList;
+ if( !pEList ) return SQLITE_ERROR;
+ for(i=0; i<pEList->nExpr; i++){
+ Expr *pX = pEList->a[i].pExpr;
+ if( sqlite3ExprResolveNames(&sNC, pX) ){
+ return SQLITE_ERROR;
+ }
+ }
+
+ /* If there are no aggregate functions in the result-set, and no GROUP BY
+ ** expression, do not allow aggregates in any of the other expressions.
+ */
+ assert( !p->isAgg );
+ pGroupBy = p->pGroupBy;
+ if( pGroupBy || sNC.hasAgg ){
+ p->isAgg = 1;
+ }else{
+ sNC.allowAgg = 0;
+ }
+
+ /* If a HAVING clause is present, then there must be a GROUP BY clause.
+ */
+ if( p->pHaving && !pGroupBy ){
+ sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
+ return SQLITE_ERROR;
+ }
+
+ /* Add the expression list to the name-context before parsing the
+ ** other expressions in the SELECT statement. This is so that
+ ** expressions in the WHERE clause (etc.) can refer to expressions by
+ ** aliases in the result set.
+ **
+ ** Minor point: If this is the case, then the expression will be
+ ** re-evaluated for each reference to it.
+ */
+ sNC.pEList = p->pEList;
+ if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
+ sqlite3ExprResolveNames(&sNC, p->pHaving) ){
+ return SQLITE_ERROR;
+ }
+ if( p->pPrior==0 ){
+ if( processOrderGroupBy(pParse, p, p->pOrderBy, 1, &sNC.hasAgg) ){
+ return SQLITE_ERROR;
+ }
+ }
+ if( processOrderGroupBy(pParse, p, pGroupBy, 0, &sNC.hasAgg) ){
+ return SQLITE_ERROR;
+ }
+
+ if( pParse->db->mallocFailed ){
+ return SQLITE_NOMEM;
+ }
+
+ /* Make sure the GROUP BY clause does not contain aggregate functions.
+ */
+ if( pGroupBy ){
+ struct ExprList_item *pItem;
+
+ for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
+ if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
+ sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
+ "the GROUP BY clause");
+ return SQLITE_ERROR;
+ }
+ }
+ }
+
+ /* If this is one SELECT of a compound, be sure to resolve names
+ ** in the other SELECTs.
+ */
+ if( p->pPrior ){
+ return sqlite3SelectResolve(pParse, p->pPrior, pOuterNC);
+ }else{
+ return SQLITE_OK;
+ }
+}
+
+/*
+** Reset the aggregate accumulator.
+**
+** The aggregate accumulator is a set of memory cells that hold
+** intermediate results while calculating an aggregate. This
+** routine simply stores NULLs in all of those memory cells.
+*/
+static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ struct AggInfo_func *pFunc;
+ if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
+ return;
+ }
+ for(i=0; i<pAggInfo->nColumn; i++){
+ sqlite3VdbeAddOp2(v, OP_Null, 0, pAggInfo->aCol[i].iMem);
+ }
+ for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
+ sqlite3VdbeAddOp2(v, OP_Null, 0, pFunc->iMem);
+ if( pFunc->iDistinct>=0 ){
+ Expr *pE = pFunc->pExpr;
+ if( pE->pList==0 || pE->pList->nExpr!=1 ){
+ sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
+ "by an expression");
+ pFunc->iDistinct = -1;
+ }else{
+ KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
+ sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
+ (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+ }
+ }
+ }
+}
+
+/*
+** Invoke the OP_AggFinalize opcode for every aggregate function
+** in the AggInfo structure.
+*/
+static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ struct AggInfo_func *pF;
+ for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+ ExprList *pList = pF->pExpr->pList;
+ sqlite3VdbeAddOp4(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0, 0,
+ (void*)pF->pFunc, P4_FUNCDEF);
+ }
+}
+
+/*
+** Update the accumulator memory cells for an aggregate based on
+** the current cursor position.
+*/
+static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ struct AggInfo_func *pF;
+ struct AggInfo_col *pC;
+
+ pAggInfo->directMode = 1;
+ for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+ int nArg;
+ int addrNext = 0;
+ int regAgg;
+ ExprList *pList = pF->pExpr->pList;
+ if( pList ){
+ nArg = pList->nExpr;
+ regAgg = sqlite3GetTempRange(pParse, nArg);
+ sqlite3ExprCodeExprList(pParse, pList, regAgg, 0);
+ }else{
+ nArg = 0;
+ regAgg = 0;
+ }
+ if( pF->iDistinct>=0 ){
+ addrNext = sqlite3VdbeMakeLabel(v);
+ assert( nArg==1 );
+ codeDistinct(pParse, pF->iDistinct, addrNext, 1, regAgg);
+ }
+ if( pF->pFunc->needCollSeq ){
+ CollSeq *pColl = 0;
+ struct ExprList_item *pItem;
+ int j;
+ assert( pList!=0 ); /* pList!=0 if pF->pFunc->needCollSeq is true */
+ for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
+ pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
+ }
+ if( !pColl ){
+ pColl = pParse->db->pDfltColl;
+ }
+ sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+ }
+ sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
+ (void*)pF->pFunc, P4_FUNCDEF);
+ sqlite3VdbeChangeP5(v, nArg);
+ sqlite3ReleaseTempRange(pParse, regAgg, nArg);
+ sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
+ if( addrNext ){
+ sqlite3VdbeResolveLabel(v, addrNext);
+ }
+ }
+ for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
+ sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
+ }
+ pAggInfo->directMode = 0;
+}
+
+/*
+** Generate code for the given SELECT statement.
+**
+** The results are distributed in various ways depending on the
+** contents of the SelectDest structure pointed to by argument pDest
+** as follows:
+**
+** pDest->eDest Result
+** ------------ -------------------------------------------
+** SRT_Callback Invoke the callback for each row of the result.
+**
+** SRT_Mem Store first result in memory cell pDest->iParm
+**
+** SRT_Set Store results as keys of table pDest->iParm.
+** Apply the affinity pDest->affinity before storing them.
+**
+** SRT_Union Store results as a key in a temporary table pDest->iParm.
+**
+** SRT_Except Remove results from the temporary table pDest->iParm.
+**
+** SRT_Table Store results in temporary table pDest->iParm
+**
+** SRT_EphemTab Create an temporary table pDest->iParm and store
+** the result there. The cursor is left open after
+** returning.
+**
+** SRT_Coroutine Invoke a co-routine to compute a single row of
+** the result
+**
+** SRT_Exists Store a 1 in memory cell pDest->iParm if the result
+** set is not empty.
+**
+** SRT_Discard Throw the results away.
+**
+** See the selectInnerLoop() function for a canonical listing of the
+** allowed values of eDest and their meanings.
+**
+** This routine returns the number of errors. If any errors are
+** encountered, then an appropriate error message is left in
+** pParse->zErrMsg.
+**
+** This routine does NOT free the Select structure passed in. The
+** calling function needs to do that.
+**
+** The pParent, parentTab, and *pParentAgg fields are filled in if this
+** SELECT is a subquery. This routine may try to combine this SELECT
+** with its parent to form a single flat query. In so doing, it might
+** change the parent query from a non-aggregate to an aggregate query.
+** For that reason, the pParentAgg flag is passed as a pointer, so it
+** can be changed.
+**
+** Example 1: The meaning of the pParent parameter.
+**
+** SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3;
+** \ \_______ subquery _______/ /
+** \ /
+** \____________________ outer query ___________________/
+**
+** This routine is called for the outer query first. For that call,
+** pParent will be NULL. During the processing of the outer query, this
+** routine is called recursively to handle the subquery. For the recursive
+** call, pParent will point to the outer query. Because the subquery is
+** the second element in a three-way join, the parentTab parameter will
+** be 1 (the 2nd value of a 0-indexed array.)
+*/
+int sqlite3Select(
+ Parse *pParse, /* The parser context */
+ Select *p, /* The SELECT statement being coded. */
+ SelectDest *pDest, /* What to do with the query results */
+ Select *pParent, /* Another SELECT for which this is a sub-query */
+ int parentTab, /* Index in pParent->pSrc of this query */
+ int *pParentAgg /* True if pParent uses aggregate functions */
+){
+ int i, j; /* Loop counters */
+ WhereInfo *pWInfo; /* Return from sqlite3WhereBegin() */
+ Vdbe *v; /* The virtual machine under construction */
+ int isAgg; /* True for select lists like "count(*)" */
+ ExprList *pEList; /* List of columns to extract. */
+ SrcList *pTabList; /* List of tables to select from */
+ Expr *pWhere; /* The WHERE clause. May be NULL */
+ ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
+ ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
+ Expr *pHaving; /* The HAVING clause. May be NULL */
+ int isDistinct; /* True if the DISTINCT keyword is present */
+ int distinct; /* Table to use for the distinct set */
+ int rc = 1; /* Value to return from this function */
+ int addrSortIndex; /* Address of an OP_OpenEphemeral instruction */
+ AggInfo sAggInfo; /* Information used by aggregate queries */
+ int iEnd; /* Address of the end of the query */
+ sqlite3 *db; /* The database connection */
+
+ db = pParse->db;
+ if( p==0 || db->mallocFailed || pParse->nErr ){
+ return 1;
+ }
+ if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
+ memset(&sAggInfo, 0, sizeof(sAggInfo));
+
+ pOrderBy = p->pOrderBy;
+ if( IgnorableOrderby(pDest) ){
+ p->pOrderBy = 0;
+
+ /* In these cases the DISTINCT operator makes no difference to the
+ ** results, so remove it if it were specified.
+ */
+ assert(pDest->eDest==SRT_Exists || pDest->eDest==SRT_Union ||
+ pDest->eDest==SRT_Except || pDest->eDest==SRT_Discard);
+ p->isDistinct = 0;
+ }
+ if( sqlite3SelectResolve(pParse, p, 0) ){
+ goto select_end;
+ }
+ p->pOrderBy = pOrderBy;
+
+
+ /* Make local copies of the parameters for this query.
+ */
+ pTabList = p->pSrc;
+ isAgg = p->isAgg;
+ pEList = p->pEList;
+ if( pEList==0 ) goto select_end;
+
+ /*
+ ** Do not even attempt to generate any code if we have already seen
+ ** errors before this routine starts.
+ */
+ if( pParse->nErr>0 ) goto select_end;
+
+ /* ORDER BY is ignored for some destinations.
+ */
+ if( IgnorableOrderby(pDest) ){
+ pOrderBy = 0;
+ }
+
+ /* Begin generating code.
+ */
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ) goto select_end;
+
+ /* Generate code for all sub-queries in the FROM clause
+ */
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+ for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
+ struct SrcList_item *pItem = &pTabList->a[i];
+ SelectDest dest;
+ Select *pSub = pItem->pSelect;
+ int isAggSub;
+ char *zName = pItem->zName;
+
+ if( pSub==0 || pItem->isPopulated ) continue;
+ if( zName!=0 ){ /* An sql view */
+ const char *zSavedAuthContext = pParse->zAuthContext;
+ pParse->zAuthContext = zName;
+ rc = sqlite3SelectResolve(pParse, pSub, 0);
+ pParse->zAuthContext = zSavedAuthContext;
+ if( rc ){
+ goto select_end;
+ }
+ }
+
+ /* Increment Parse.nHeight by the height of the largest expression
+ ** tree refered to by this, the parent select. The child select
+ ** may contain expression trees of at most
+ ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
+ ** more conservative than necessary, but much easier than enforcing
+ ** an exact limit.
+ */
+ pParse->nHeight += sqlite3SelectExprHeight(p);
+
+ /* Check to see if the subquery can be absorbed into the parent. */
+ isAggSub = pSub->isAgg;
+ if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
+ if( isAggSub ){
+ p->isAgg = isAgg = 1;
+ }
+ i = -1;
+ }else{
+ sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
+ sqlite3Select(pParse, pSub, &dest, p, i, &isAgg);
+ }
+ if( pParse->nErr || db->mallocFailed ){
+ goto select_end;
+ }
+ pParse->nHeight -= sqlite3SelectExprHeight(p);
+ pTabList = p->pSrc;
+ if( !IgnorableOrderby(pDest) ){
+ pOrderBy = p->pOrderBy;
+ }
+ }
+ pEList = p->pEList;
+#endif
+ pWhere = p->pWhere;
+ pGroupBy = p->pGroupBy;
+ pHaving = p->pHaving;
+ isDistinct = p->isDistinct;
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+ /* If there is are a sequence of queries, do the earlier ones first.
+ */
+ if( p->pPrior ){
+ if( p->pRightmost==0 ){
+ Select *pLoop, *pRight = 0;
+ int cnt = 0;
+ int mxSelect;
+ for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
+ pLoop->pRightmost = p;
+ pLoop->pNext = pRight;
+ pRight = pLoop;
+ }
+ mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
+ if( mxSelect && cnt>mxSelect ){
+ sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
+ return 1;
+ }
+ }
+ return multiSelect(pParse, p, pDest);
+ }
+#endif
+
+ /* If writing to memory or generating a set
+ ** only a single column may be output.
+ */
+#ifndef SQLITE_OMIT_SUBQUERY
+ if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
+ goto select_end;
+ }
+#endif
+
+ /* If possible, rewrite the query to use GROUP BY instead of DISTINCT.
+ ** GROUP BY may use an index, DISTINCT never does.
+ */
+ if( p->isDistinct && !p->isAgg && !p->pGroupBy ){
+ p->pGroupBy = sqlite3ExprListDup(db, p->pEList);
+ pGroupBy = p->pGroupBy;
+ p->isDistinct = 0;
+ isDistinct = 0;
+ }
+
+ /* If there is an ORDER BY clause, then this sorting
+ ** index might end up being unused if the data can be
+ ** extracted in pre-sorted order. If that is the case, then the
+ ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
+ ** we figure out that the sorting index is not needed. The addrSortIndex
+ ** variable is used to facilitate that change.
+ */
+ if( pOrderBy ){
+ KeyInfo *pKeyInfo;
+ pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
+ pOrderBy->iECursor = pParse->nTab++;
+ p->addrOpenEphm[2] = addrSortIndex =
+ sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+ pOrderBy->iECursor, pOrderBy->nExpr+2, 0,
+ (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+ }else{
+ addrSortIndex = -1;
+ }
+
+ /* If the output is destined for a temporary table, open that table.
+ */
+ if( pDest->eDest==SRT_EphemTab ){
+ sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iParm, pEList->nExpr);
+ }
+
+ /* Set the limiter.
+ */
+ iEnd = sqlite3VdbeMakeLabel(v);
+ computeLimitRegisters(pParse, p, iEnd);
+
+ /* Open a virtual index to use for the distinct set.
+ */
+ if( isDistinct ){
+ KeyInfo *pKeyInfo;
+ assert( isAgg || pGroupBy );
+ distinct = pParse->nTab++;
+ pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
+ sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0,
+ (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+ }else{
+ distinct = -1;
+ }
+
+ /* Aggregate and non-aggregate queries are handled differently */
+ if( !isAgg && pGroupBy==0 ){
+ /* This case is for non-aggregate queries
+ ** Begin the database scan
+ */
+ pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, 0);
+ if( pWInfo==0 ) goto select_end;
+
+ /* If sorting index that was created by a prior OP_OpenEphemeral
+ ** instruction ended up not being needed, then change the OP_OpenEphemeral
+ ** into an OP_Noop.
+ */
+ if( addrSortIndex>=0 && pOrderBy==0 ){
+ sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
+ p->addrOpenEphm[2] = -1;
+ }
+
+ /* Use the standard inner loop
+ */
+ assert(!isDistinct);
+ selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
+ pWInfo->iContinue, pWInfo->iBreak);
+
+ /* End the database scan loop.
+ */
+ sqlite3WhereEnd(pWInfo);
+ }else{
+ /* This is the processing for aggregate queries */
+ NameContext sNC; /* Name context for processing aggregate information */
+ int iAMem; /* First Mem address for storing current GROUP BY */
+ int iBMem; /* First Mem address for previous GROUP BY */
+ int iUseFlag; /* Mem address holding flag indicating that at least
+ ** one row of the input to the aggregator has been
+ ** processed */
+ int iAbortFlag; /* Mem address which causes query abort if positive */
+ int groupBySort; /* Rows come from source in GROUP BY order */
+
+
+ /* The following variables hold addresses or labels for parts of the
+ ** virtual machine program we are putting together */
+ int addrOutputRow; /* Start of subroutine that outputs a result row */
+ int regOutputRow; /* Return address register for output subroutine */
+ int addrSetAbort; /* Set the abort flag and return */
+ int addrInitializeLoop; /* Start of code that initializes the input loop */
+ int addrTopOfLoop; /* Top of the input loop */
+ int addrEnd; /* End of all processing */
+ int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
+ int addrReset; /* Subroutine for resetting the accumulator */
+ int regReset; /* Return address register for reset subroutine */
+
+ addrEnd = sqlite3VdbeMakeLabel(v);
+
+ /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
+ ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
+ ** SELECT statement.
+ */
+ memset(&sNC, 0, sizeof(sNC));
+ sNC.pParse = pParse;
+ sNC.pSrcList = pTabList;
+ sNC.pAggInfo = &sAggInfo;
+ sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
+ sAggInfo.pGroupBy = pGroupBy;
+ sqlite3ExprAnalyzeAggList(&sNC, pEList);
+ sqlite3ExprAnalyzeAggList(&sNC, pOrderBy);
+ if( pHaving ){
+ sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
+ }
+ sAggInfo.nAccumulator = sAggInfo.nColumn;
+ for(i=0; i<sAggInfo.nFunc; i++){
+ sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList);
+ }
+ if( db->mallocFailed ) goto select_end;
+
+ /* Processing for aggregates with GROUP BY is very different and
+ ** much more complex than aggregates without a GROUP BY.
+ */
+ if( pGroupBy ){
+ KeyInfo *pKeyInfo; /* Keying information for the group by clause */
+ int j1;
+
+ /* Create labels that we will be needing
+ */
+ addrInitializeLoop = sqlite3VdbeMakeLabel(v);
+
+ /* If there is a GROUP BY clause we might need a sorting index to
+ ** implement it. Allocate that sorting index now. If it turns out
+ ** that we do not need it after all, the OpenEphemeral instruction
+ ** will be converted into a Noop.
+ */
+ sAggInfo.sortingIdx = pParse->nTab++;
+ pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
+ addrSortingIdx = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+ sAggInfo.sortingIdx, sAggInfo.nSortingColumn,
+ 0, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
+
+ /* Initialize memory locations used by GROUP BY aggregate processing
+ */
+ iUseFlag = ++pParse->nMem;
+ iAbortFlag = ++pParse->nMem;
+ iAMem = pParse->nMem + 1;
+ pParse->nMem += pGroupBy->nExpr;
+ iBMem = pParse->nMem + 1;
+ pParse->nMem += pGroupBy->nExpr;
+ sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
+ VdbeComment((v, "clear abort flag"));
+ sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
+ VdbeComment((v, "indicate accumulator empty"));
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, addrInitializeLoop);
+
+ /* Generate a subroutine that outputs a single row of the result
+ ** set. This subroutine first looks at the iUseFlag. If iUseFlag
+ ** is less than or equal to zero, the subroutine is a no-op. If
+ ** the processing calls for the query to abort, this subroutine
+ ** increments the iAbortFlag memory location before returning in
+ ** order to signal the caller to abort.
+ */
+ addrSetAbort = sqlite3VdbeCurrentAddr(v);
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
+ VdbeComment((v, "set abort flag"));
+ regOutputRow = ++pParse->nMem;
+ sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+ addrOutputRow = sqlite3VdbeCurrentAddr(v);
+ sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
+ VdbeComment((v, "Groupby result generator entry point"));
+ sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+ finalizeAggFunctions(pParse, &sAggInfo);
+ if( pHaving ){
+ sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
+ }
+ selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
+ distinct, pDest,
+ addrOutputRow+1, addrSetAbort);
+ sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+ VdbeComment((v, "end groupby result generator"));
+
+ /* Generate a subroutine that will reset the group-by accumulator
+ */
+ addrReset = sqlite3VdbeCurrentAddr(v);
+ regReset = ++pParse->nMem;
+ resetAccumulator(pParse, &sAggInfo);
+ sqlite3VdbeAddOp1(v, OP_Return, regReset);
+
+ /* Begin a loop that will extract all source rows in GROUP BY order.
+ ** This might involve two separate loops with an OP_Sort in between, or
+ ** it might be a single loop that uses an index to extract information
+ ** in the right order to begin with.
+ */
+ sqlite3VdbeResolveLabel(v, addrInitializeLoop);
+ sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
+ pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0);
+ if( pWInfo==0 ) goto select_end;
+ if( pGroupBy==0 ){
+ /* The optimizer is able to deliver rows in group by order so
+ ** we do not have to sort. The OP_OpenEphemeral table will be
+ ** cancelled later because we still need to use the pKeyInfo
+ */
+ pGroupBy = p->pGroupBy;
+ groupBySort = 0;
+ }else{
+ /* Rows are coming out in undetermined order. We have to push
+ ** each row into a sorting index, terminate the first loop,
+ ** then loop over the sorting index in order to get the output
+ ** in sorted order
+ */
+ int regBase;
+ int regRecord;
+ int nCol;
+ int nGroupBy;
+
+ groupBySort = 1;
+ nGroupBy = pGroupBy->nExpr;
+ nCol = nGroupBy + 1;
+ j = nGroupBy+1;
+ for(i=0; i<sAggInfo.nColumn; i++){
+ if( sAggInfo.aCol[i].iSorterColumn>=j ){
+ nCol++;
+ j++;
+ }
+ }
+ regBase = sqlite3GetTempRange(pParse, nCol);
+ sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0);
+ sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx,regBase+nGroupBy);
+ j = nGroupBy+1;
+ for(i=0; i<sAggInfo.nColumn; i++){
+ struct AggInfo_col *pCol = &sAggInfo.aCol[i];
+ if( pCol->iSorterColumn>=j ){
+ int r1 = j + regBase;
+#ifndef NDEBUG
+ int r2 =
+#endif
+ sqlite3ExprCodeGetColumn(pParse,
+ pCol->pTab, pCol->iColumn, pCol->iTable, r1, 0);
+ j++;
+
+ /* sAggInfo.aCol[] only contains one entry per column. So
+ ** The reference to pCol->iColumn,pCol->iTable must have been
+ ** the first reference to that column. Hence,
+ ** sqliteExprCodeGetColumn is guaranteed to put the result in
+ ** the column requested.
+ */
+ assert( r1==r2 );
+ }
+ }
+ regRecord = sqlite3GetTempReg(pParse);
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, sAggInfo.sortingIdx, regRecord);
+ sqlite3ReleaseTempReg(pParse, regRecord);
+ sqlite3ReleaseTempRange(pParse, regBase, nCol);
+ sqlite3WhereEnd(pWInfo);
+ sqlite3VdbeAddOp2(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
+ VdbeComment((v, "GROUP BY sort"));
+ sAggInfo.useSortingIdx = 1;
+ }
+
+ /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
+ ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
+ ** Then compare the current GROUP BY terms against the GROUP BY terms
+ ** from the previous row currently stored in a0, a1, a2...
+ */
+ addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
+ for(j=0; j<pGroupBy->nExpr; j++){
+ if( groupBySort ){
+ sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
+ }else{
+ sAggInfo.directMode = 1;
+ sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
+ }
+ }
+ sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
+ (char*)pKeyInfo, P4_KEYINFO);
+ j1 = sqlite3VdbeCurrentAddr(v);
+ sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);
+
+ /* Generate code that runs whenever the GROUP BY changes.
+ ** Changes in the GROUP BY are detected by the previous code
+ ** block. If there were no changes, this block is skipped.
+ **
+ ** This code copies current group by terms in b0,b1,b2,...
+ ** over to a0,a1,a2. It then calls the output subroutine
+ ** and resets the aggregate accumulator registers in preparation
+ ** for the next GROUP BY batch.
+ */
+ sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);
+ sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
+ VdbeComment((v, "output one row"));
+ sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
+ VdbeComment((v, "check abort flag"));
+ sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
+ VdbeComment((v, "reset accumulator"));
+
+ /* Update the aggregate accumulators based on the content of
+ ** the current row
+ */
+ sqlite3VdbeJumpHere(v, j1);
+ updateAccumulator(pParse, &sAggInfo);
+ sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
+ VdbeComment((v, "indicate data in accumulator"));
+
+ /* End of the loop
+ */
+ if( groupBySort ){
+ sqlite3VdbeAddOp2(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
+ }else{
+ sqlite3WhereEnd(pWInfo);
+ sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
+ }
+
+ /* Output the final row of result
+ */
+ sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
+ VdbeComment((v, "output final row"));
+
+ } /* endif pGroupBy */
+ else {
+ ExprList *pMinMax = 0;
+ ExprList *pDel = 0;
+ u8 flag;
+
+ /* Check if the query is of one of the following forms:
+ **
+ ** SELECT min(x) FROM ...
+ ** SELECT max(x) FROM ...
+ **
+ ** If it is, then ask the code in where.c to attempt to sort results
+ ** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause.
+ ** If where.c is able to produce results sorted in this order, then
+ ** add vdbe code to break out of the processing loop after the
+ ** first iteration (since the first iteration of the loop is
+ ** guaranteed to operate on the row with the minimum or maximum
+ ** value of x, the only row required).
+ **
+ ** A special flag must be passed to sqlite3WhereBegin() to slightly
+ ** modify behaviour as follows:
+ **
+ ** + If the query is a "SELECT min(x)", then the loop coded by
+ ** where.c should not iterate over any values with a NULL value
+ ** for x.
+ **
+ ** + The optimizer code in where.c (the thing that decides which
+ ** index or indices to use) should place a different priority on
+ ** satisfying the 'ORDER BY' clause than it does in other cases.
+ ** Refer to code and comments in where.c for details.
+ */
+ flag = minMaxQuery(pParse, p);
+ if( flag ){
+ pDel = pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->pList);
+ if( pMinMax && !db->mallocFailed ){
+ pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN;
+ pMinMax->a[0].pExpr->op = TK_COLUMN;
+ }
+ }
+
+ /* This case runs if the aggregate has no GROUP BY clause. The
+ ** processing is much simpler since there is only a single row
+ ** of output.
+ */
+ resetAccumulator(pParse, &sAggInfo);
+ pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax, flag);
+ if( pWInfo==0 ){
+ sqlite3ExprListDelete(db, pDel);
+ goto select_end;
+ }
+ updateAccumulator(pParse, &sAggInfo);
+ if( !pMinMax && flag ){
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
+ VdbeComment((v, "%s() by index",(flag==WHERE_ORDERBY_MIN?"min":"max")));
+ }
+ sqlite3WhereEnd(pWInfo);
+ finalizeAggFunctions(pParse, &sAggInfo);
+ pOrderBy = 0;
+ if( pHaving ){
+ sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
+ }
+ selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1,
+ pDest, addrEnd, addrEnd);
+
+ sqlite3ExprListDelete(db, pDel);
+ }
+ sqlite3VdbeResolveLabel(v, addrEnd);
+
+ } /* endif aggregate query */
+
+ /* If there is an ORDER BY clause, then we need to sort the results
+ ** and send them to the callback one by one.
+ */
+ if( pOrderBy ){
+ generateSortTail(pParse, p, v, pEList->nExpr, pDest);
+ }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+ /* If this was a subquery, we have now converted the subquery into a
+ ** temporary table. So set the SrcList_item.isPopulated flag to prevent
+ ** this subquery from being evaluated again and to force the use of
+ ** the temporary table.
+ */
+ if( pParent ){
+ assert( pParent->pSrc->nSrc>parentTab );
+ assert( pParent->pSrc->a[parentTab].pSelect==p );
+ pParent->pSrc->a[parentTab].isPopulated = 1;
+ }
+#endif
+
+ /* Jump here to skip this query
+ */
+ sqlite3VdbeResolveLabel(v, iEnd);
+
+ /* The SELECT was successfully coded. Set the return code to 0
+ ** to indicate no errors.
+ */
+ rc = 0;
+
+ /* Control jumps to here if an error is encountered above, or upon
+ ** successful coding of the SELECT.
+ */
+select_end:
+
+ /* Identify column names if we will be using them in a callback. This
+ ** step is skipped if the output is going to some other destination.
+ */
+ if( rc==SQLITE_OK && pDest->eDest==SRT_Callback ){
+ generateColumnNames(pParse, pTabList, pEList);
+ }
+
+ sqlite3DbFree(db, sAggInfo.aCol);
+ sqlite3DbFree(db, sAggInfo.aFunc);
+ return rc;
+}
+
+#if defined(SQLITE_DEBUG)
+/*
+*******************************************************************************
+** The following code is used for testing and debugging only. The code
+** that follows does not appear in normal builds.
+**
+** These routines are used to print out the content of all or part of a
+** parse structures such as Select or Expr. Such printouts are useful
+** for helping to understand what is happening inside the code generator
+** during the execution of complex SELECT statements.
+**
+** These routine are not called anywhere from within the normal
+** code base. Then are intended to be called from within the debugger
+** or from temporary "printf" statements inserted for debugging.
+*/
+void sqlite3PrintExpr(Expr *p){
+ if( p->token.z && p->token.n>0 ){
+ sqlite3DebugPrintf("(%.*s", p->token.n, p->token.z);
+ }else{
+ sqlite3DebugPrintf("(%d", p->op);
+ }
+ if( p->pLeft ){
+ sqlite3DebugPrintf(" ");
+ sqlite3PrintExpr(p->pLeft);
+ }
+ if( p->pRight ){
+ sqlite3DebugPrintf(" ");
+ sqlite3PrintExpr(p->pRight);
+ }
+ sqlite3DebugPrintf(")");
+}
+void sqlite3PrintExprList(ExprList *pList){
+ int i;
+ for(i=0; i<pList->nExpr; i++){
+ sqlite3PrintExpr(pList->a[i].pExpr);
+ if( i<pList->nExpr-1 ){
+ sqlite3DebugPrintf(", ");
+ }
+ }
+}
+void sqlite3PrintSelect(Select *p, int indent){
+ sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
+ sqlite3PrintExprList(p->pEList);
+ sqlite3DebugPrintf("\n");
+ if( p->pSrc ){
+ char *zPrefix;
+ int i;
+ zPrefix = "FROM";
+ for(i=0; i<p->pSrc->nSrc; i++){
+ struct SrcList_item *pItem = &p->pSrc->a[i];
+ sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
+ zPrefix = "";
+ if( pItem->pSelect ){
+ sqlite3DebugPrintf("(\n");
+ sqlite3PrintSelect(pItem->pSelect, indent+10);
+ sqlite3DebugPrintf("%*s)", indent+8, "");
+ }else if( pItem->zName ){
+ sqlite3DebugPrintf("%s", pItem->zName);
+ }
+ if( pItem->pTab ){
+ sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
+ }
+ if( pItem->zAlias ){
+ sqlite3DebugPrintf(" AS %s", pItem->zAlias);
+ }
+ if( i<p->pSrc->nSrc-1 ){
+ sqlite3DebugPrintf(",");
+ }
+ sqlite3DebugPrintf("\n");
+ }
+ }
+ if( p->pWhere ){
+ sqlite3DebugPrintf("%*s WHERE ", indent, "");
+ sqlite3PrintExpr(p->pWhere);
+ sqlite3DebugPrintf("\n");
+ }
+ if( p->pGroupBy ){
+ sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
+ sqlite3PrintExprList(p->pGroupBy);
+ sqlite3DebugPrintf("\n");
+ }
+ if( p->pHaving ){
+ sqlite3DebugPrintf("%*s HAVING ", indent, "");
+ sqlite3PrintExpr(p->pHaving);
+ sqlite3DebugPrintf("\n");
+ }
+ if( p->pOrderBy ){
+ sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
+ sqlite3PrintExprList(p->pOrderBy);
+ sqlite3DebugPrintf("\n");
+ }
+}
+/* End of the structure debug printing code
+*****************************************************************************/
+#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */