--- a/engine/sqlite/src/select.cpp Wed May 26 10:44:32 2010 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,3667 +0,0 @@
-/*
-** 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.cpp 1282 2008-11-13 09:31:33Z LarsPson $
-*/
-#include "sqliteInt.h"
-
-
-/*
-** Delete all the content of a Select structure but do not deallocate
-** the select structure itself.
-*/
-static void clearSelect(Select *p){
- sqlite3ExprListDelete(p->pEList);
- sqlite3SrcListDelete(p->pSrc);
- sqlite3ExprDelete(p->pWhere);
- sqlite3ExprListDelete(p->pGroupBy);
- sqlite3ExprDelete(p->pHaving);
- sqlite3ExprListDelete(p->pOrderBy);
- sqlite3SelectDelete(p->pPrior);
- sqlite3ExprDelete(p->pLimit);
- sqlite3ExprDelete(p->pOffset);
-}
-
-
-/*
-** 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 = (Select*)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->iLimit = -1;
- pNew->iOffset = -1;
- pNew->addrOpenEphm[0] = -1;
- pNew->addrOpenEphm[1] = -1;
- pNew->addrOpenEphm[2] = -1;
- if( pNew==&standin) {
- clearSelect(pNew);
- pNew = 0;
- }
- return pNew;
-}
-
-/*
-** Delete the given Select structure and all of its substructures.
-*/
-void sqlite3SelectDelete(Select *p){
- if( p ){
- clearSelect(p);
- sqlite3_free(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 *zSp1 = " ";
- const char *zSp2 = " ";
- if( pB==0 ){ zSp1++; }
- if( pC==0 ){ zSp2++; }
- sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
- "%T%s%T%s%T", pA, zSp1, pB, zSp2, 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){
- p->z = (u8 *)sqlite3MPrintf(0, "\"%w\"", z);
- p->dyn = 1;
- if( p->z ){
- p->n = strlen((char *)p->z);
- }else{
- pParse->db->mallocFailed = 1;
- }
-}
-
-/*
-** 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 */
-){
- 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 ){
- 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 */
- SrcList::SrcList_item *pLeft; /* Left table being joined */
- SrcList::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;
-
- if( pLeftTab==0 || pRightTab==0 ) continue;
-
- /* 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);
-
- }
- }
- }
-
- /* 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 ){
- 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);
- }
- }
- }
- 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 */
-){
- Vdbe *v = pParse->pVdbe;
- sqlite3ExprCodeExprList(pParse, pOrderBy);
- sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0);
- sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0);
- sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
- sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
- if( pSelect->iLimit>=0 ){
- int addr1, addr2;
- addr1 = sqlite3VdbeAddOp(v, OP_IfMemZero, pSelect->iLimit+1, 0);
- sqlite3VdbeAddOp(v, OP_MemIncr, -1, pSelect->iLimit+1);
- addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
- sqlite3VdbeJumpHere(v, addr1);
- sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
- sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
- sqlite3VdbeJumpHere(v, addr2);
- pSelect->iLimit = -1;
- }
-}
-
-/*
-** 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 */
- int nPop /* Number of times to pop stack when jumping */
-){
- if( p->iOffset>=0 && iContinue!=0 ){
- int addr;
- sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iOffset);
- addr = sqlite3VdbeAddOp(v, OP_IfMemNeg, p->iOffset, 0);
- if( nPop>0 ){
- sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
- }
- sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
- VdbeComment((v, "# skip OFFSET records"));
- sqlite3VdbeJumpHere(v, addr);
- }
-}
-
-/*
-** Add code that will check to make sure the top N elements of the
-** stack are distinct. 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(
- Vdbe *v, /* Generate code into this VM */
- int iTab, /* A sorting index used to test for distinctness */
- int addrRepeat, /* Jump to here if not distinct */
- int N /* The top N elements of the stack must be distinct */
-){
- sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
- sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
- sqlite3VdbeAddOp(v, OP_Pop, N+1, 0);
- sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
- VdbeComment((v, "# skip indistinct records"));
- sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
-}
-
-/*
-** 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, int eDest, int nExpr){
- 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 int 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 */
- int eDest, /* How to dispose of the results */
- int iParm, /* An argument to the disposal method */
- int iContinue, /* Jump here to continue with next row */
- int iBreak, /* Jump here to break out of the inner loop */
- char *aff /* affinity string if eDest is SRT_Union */
-){
- Vdbe *v = pParse->pVdbe;
- int i;
- int hasDistinct; /* True if the DISTINCT keyword is present */
-
- if( v==0 ) return 0;
- assert( pEList!=0 );
-
- /* If there was a LIMIT clause on the SELECT statement, then do the check
- ** to see if this row should be output.
- */
- hasDistinct = distinct>=0 && pEList->nExpr>0;
- if( pOrderBy==0 && !hasDistinct ){
- codeOffset(v, p, iContinue, 0);
- }
-
- /* Pull the requested columns.
- */
- if( nColumn>0 ){
- for(i=0; i<nColumn; i++){
- sqlite3VdbeAddOp(v, OP_Column, srcTab, i);
- }
- }else{
- nColumn = pEList->nExpr;
- sqlite3ExprCodeExprList(pParse, pEList);
- }
-
- /* 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(v, distinct, iContinue, nColumn);
- if( pOrderBy==0 ){
- codeOffset(v, p, iContinue, nColumn);
- }
- }
-
- if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
- return 0;
- }
-
- 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: {
- sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
- if( aff ){
- sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
- }
- sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
- 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: {
- int addr;
- addr = sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
- sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
- sqlite3VdbeAddOp(v, OP_NotFound, iParm, addr+3);
- sqlite3VdbeAddOp(v, OP_Delete, iParm, 0);
- break;
- }
-#endif
-
- /* Store the result as data using a unique key.
- */
- case SRT_Table:
- case SRT_EphemTab: {
- sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
- if( pOrderBy ){
- pushOntoSorter(pParse, pOrderBy, p);
- }else{
- sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
- sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
- sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
- }
- 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 addr1 = sqlite3VdbeCurrentAddr(v);
- int addr2;
-
- assert( nColumn==1 );
- sqlite3VdbeAddOp(v, OP_NotNull, -1, addr1+3);
- sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
- addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
- p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr,(iParm>>16)&0xff);
- 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);
- }else{
- sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &p->affinity, 1);
- sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
- }
- sqlite3VdbeJumpHere(v, addr2);
- break;
- }
-
- /* If any row exist in the result set, record that fact and abort.
- */
- case SRT_Exists: {
- sqlite3VdbeAddOp(v, OP_MemInt, 1, iParm);
- sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
- /* 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);
- }else{
- sqlite3VdbeAddOp(v, OP_MemStore, 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_Subroutine:
- case SRT_Callback: {
- if( pOrderBy ){
- sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
- pushOntoSorter(pParse, pOrderBy, p);
- }else if( eDest==SRT_Subroutine ){
- sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
- }else{
- sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
- }
- 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 );
- sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
- break;
- }
-#endif
- }
-
- /* Jump to the end of the loop if the LIMIT is reached.
- */
- if( p->iLimit>=0 && pOrderBy==0 ){
- sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
- sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, iBreak);
- }
- return 0;
-}
-
-/*
-** 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 P3 field of an opcode using
-** P3_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;
- ExprList::ExprList_item *pItem;
- int i;
-
- nExpr = pList->nExpr;
- pInfo = (KeyInfo*)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 */
- int eDest, /* Write the sorted results here */
- int iParm /* Optional parameter associated with eDest */
-){
- int brk = sqlite3VdbeMakeLabel(v);
- int cont = sqlite3VdbeMakeLabel(v);
- int addr;
- int iTab;
- int pseudoTab = 0;
- ExprList *pOrderBy = p->pOrderBy;
-
- iTab = pOrderBy->iECursor;
- if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
- pseudoTab = pParse->nTab++;
- sqlite3VdbeAddOp(v, OP_OpenPseudo, pseudoTab, 0);
- sqlite3VdbeAddOp(v, OP_SetNumColumns, pseudoTab, nColumn);
- }
- addr = 1 + sqlite3VdbeAddOp(v, OP_Sort, iTab, brk);
- codeOffset(v, p, cont, 0);
- if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
- sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
- }
- sqlite3VdbeAddOp(v, OP_Column, iTab, pOrderBy->nExpr + 1);
- switch( eDest ){
- case SRT_Table:
- case SRT_EphemTab: {
- sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
- sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
- sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
- break;
- }
-#ifndef SQLITE_OMIT_SUBQUERY
- case SRT_Set: {
- assert( nColumn==1 );
- sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
- sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
- sqlite3VdbeAddOp(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
- sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &p->affinity, 1);
- sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
- break;
- }
- case SRT_Mem: {
- assert( nColumn==1 );
- sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
- /* The LIMIT clause will terminate the loop for us */
- break;
- }
-#endif
- case SRT_Callback:
- case SRT_Subroutine: {
- int i;
- sqlite3VdbeAddOp(v, OP_Insert, pseudoTab, 0);
- for(i=0; i<nColumn; i++){
- sqlite3VdbeAddOp(v, OP_Column, pseudoTab, i);
- }
- if( eDest==SRT_Callback ){
- sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
- }else{
- sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
- }
- break;
- }
- default: {
- /* Do nothing */
- break;
- }
- }
-
- /* Jump to the end of the loop when the LIMIT is reached
- */
- if( p->iLimit>=0 ){
- sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
- sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, brk);
- }
-
- /* The bottom of the loop
- */
- sqlite3VdbeResolveLabel(v, cont);
- sqlite3VdbeAddOp(v, OP_Next, iTab, addr);
- sqlite3VdbeResolveLabel(v, brk);
- if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
- sqlite3VdbeAddOp(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 */
-){
- 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 *zOrigDb = 0;
- const char *zOrigTab = 0;
- const char *zOrigCol = 0;
- const char *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_DECLTYPE, zType, P3_TRANSIENT);
- sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P3_TRANSIENT);
- sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P3_TRANSIENT);
- sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P3_TRANSIENT);
- }
-}
-
-/*
-** 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));
- continue;
- }
- 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 && p->span.z && p->span.z[0] ){
- 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;
- sqlite3SetString(&zName, zTab, ".", zCol, (char*)0);
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P3_DYNAMIC);
- }else{
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
- }
- }else if( p->span.z && p->span.z[0] ){
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
- /* sqlite3VdbeCompressSpace(v, addr); */
- }else{
- char zName[30];
- assert( p->op!=TK_COLUMN || pTabList==0 );
- sqlite3_snprintf(sizeof(zName), zName, "column%d", i+1);
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, 0);
- }
- }
- 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;
- ExprList *pEList;
- Column *aCol, *pCol;
- sqlite3 *db = pParse->db;
-
- while( pSelect->pPrior ) pSelect = pSelect->pPrior;
- if( prepSelectStmt(pParse, pSelect) ){
- return 0;
- }
- if( sqlite3SelectResolve(pParse, pSelect, 0) ){
- return 0;
- }
- pTab = (Table*)sqlite3DbMallocZero(db, sizeof(Table) );
- if( pTab==0 ){
- return 0;
- }
- pTab->nRef = 1;
- pTab->zName = zTabName ? sqlite3DbStrDup(db, zTabName) : 0;
- pEList = pSelect->pEList;
- pTab->nCol = pEList->nExpr;
- assert( pTab->nCol>0 );
- pTab->aCol = aCol = (Column*)sqlite3DbMallocZero(db, sizeof(pTab->aCol[0])*pTab->nCol);
- for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
- Expr *p, *pR;
- 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_DOT
- && (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
- /* For columns of the from A.B use B as the name */
- zName = sqlite3MPrintf(db, "%T", &pR->token);
- }else if( p->span.z && p->span.z[0] ){
- /* Use the original text of the column expression as its name */
- zName = sqlite3MPrintf(db, "%T", &p->span);
- }else{
- /* If all else fails, make up a name */
- zName = sqlite3MPrintf(db, "column%d", i+1);
- }
- if( !zName || db->mallocFailed ){
- db->mallocFailed = 1;
- sqlite3_free(zName);
- sqlite3DeleteTable(pTab);
- return 0;
- }
- 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 ){
- zName[nName] = 0;
- zName = sqlite3MPrintf(db, "%z:%d", zName, ++cnt);
- 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;
- 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;
- SrcList::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.
- */
- Table *pTab;
- for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
- 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,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.
- */
- ExprList::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;
- }
- if( zTName && (zTabName==0 || zTabName[0]==0 ||
- 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 ){
- SrcList::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( zTabName && (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);
- setToken(&pExpr->span,
- sqlite3MPrintf(db, "%s.%s", zTabName, zName));
- pExpr->span.dyn = 1;
- 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;
- }
- sqlite3_free(zTName);
- }
- }
- sqlite3ExprListDelete(pEList);
- p->pEList = pNew;
- }
- if( p->pEList && p->pEList->nExpr>SQLITE_MAX_COLUMN ){
- sqlite3ErrorMsg(pParse, "too many columns in result set");
- rc = SQLITE_ERROR;
- }
- 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.
-**
-** If pE evaluates to an integer constant i, then return i.
-** This is an indication to the caller that it should sort
-** by the i-th column of the result set.
-**
-** 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 */
-
-
- /* If the term is an integer constant, return the value of that
- ** constant */
- pEList = pSelect->pEList;
- if( sqlite3ExprIsInteger(pE, &i) ){
- if( i<=0 ){
- /* If i is too small, make it too big. That way the calling
- ** function still sees a value that is out of range, but does
- ** not confuse the column number with 0 or -1 result code.
- */
- i = pEList->nExpr+1;
- }
- return i;
- }
-
- /* 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 ){
- sqlite3_free(zCol);
- return i+1;
- }
- }
- sqlite3_free(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 ) return 0;
- if( pOrderBy->nExpr>SQLITE_MAX_COLUMN ){
- const char *zType = isOrder ? "ORDER" : "GROUP";
- sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
- return 1;
- }
- pEList = pSelect->pEList;
- if( pEList==0 ){
- return 0;
- }
- for(i=0; i<pOrderBy->nExpr; i++){
- int iCol;
- Expr *pE = pOrderBy->a[i].pExpr;
- iCol = matchOrderByTermToExprList(pParse, pSelect, pE, i+1, 0, pHasAgg);
- if( iCol<0 ){
- return 1;
- }
- if( 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;
- }
- if( iCol>0 ){
- CollSeq *pColl = pE->pColl;
- int flags = pE->flags & EP_ExpCollate;
- sqlite3ExprDelete(pE);
- pE = sqlite3ExprDup(db, pEList->a[iCol-1].pExpr);
- pOrderBy->a[i].pExpr = pE;
- if( 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.
-**
-** The processing depends on whether the SELECT is simple or compound.
-** For a simple SELECT statement, evry 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.
-**
-** For compound SELECT statements, every expression needs to be of
-** type TK_COLUMN with a iTable value as given in the 4th parameter.
-** If any expression is an integer, that becomes the column number.
-** Otherwise, match the expression against result set columns from
-** the left-most SELECT.
-*/
-static int processCompoundOrderBy(
- Parse *pParse, /* Parsing context. Leave error messages here */
- Select *pSelect, /* The SELECT statement containing the ORDER BY */
- int iTable /* Output table for compound SELECT statements */
-){
- int i;
- ExprList *pOrderBy;
- ExprList *pEList;
- sqlite3 *db;
- int moreToDo = 1;
-
- pOrderBy = pSelect->pOrderBy;
- if( pOrderBy==0 ) return 0;
- if( pOrderBy->nExpr>SQLITE_MAX_COLUMN ){
- sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
- return 1;
- }
- db = pParse->db;
- for(i=0; i<pOrderBy->nExpr; i++){
- pOrderBy->a[i].done = 0;
- }
- while( pSelect->pPrior ){
- pSelect = pSelect->pPrior;
- }
- while( pSelect && moreToDo ){
- moreToDo = 0;
- for(i=0; i<pOrderBy->nExpr; i++){
- int iCol;
- Expr *pE, *pDup;
- if( pOrderBy->a[i].done ) continue;
- pE = pOrderBy->a[i].pExpr;
- pDup = sqlite3ExprDup(db, pE);
- if( pDup==0 ){
- return 1;
- }
- iCol = matchOrderByTermToExprList(pParse, pSelect, pDup, i+1, 1, 0);
- sqlite3ExprDelete(pDup);
- if( iCol<0 ){
- return 1;
- }
- pEList = pSelect->pEList;
- if( pEList==0 ){
- return 1;
- }
- if( iCol>pEList->nExpr ){
- sqlite3ErrorMsg(pParse,
- "%r ORDER BY term out of range - should be "
- "between 1 and %d", i+1, pEList->nExpr);
- return 1;
- }
- if( iCol>0 ){
- pE->op = TK_COLUMN;
- pE->iTable = iTable;
- pE->iAgg = -1;
- pE->iColumn = iCol-1;
- pE->pTab = 0;
- 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);
- }
- 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, addr2;
-
- /*
- ** "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;
- pParse->nMem += 2;
- v = sqlite3GetVdbe(pParse);
- if( v==0 ) return;
- sqlite3ExprCode(pParse, p->pLimit);
- sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
- sqlite3VdbeAddOp(v, OP_MemStore, iLimit, 1);
- VdbeComment((v, "# LIMIT counter"));
- sqlite3VdbeAddOp(v, OP_IfMemZero, iLimit, iBreak);
- sqlite3VdbeAddOp(v, OP_MemLoad, iLimit, 0);
- }
- if( p->pOffset ){
- p->iOffset = iOffset = pParse->nMem++;
- v = sqlite3GetVdbe(pParse);
- if( v==0 ) return;
- sqlite3ExprCode(pParse, p->pOffset);
- sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
- sqlite3VdbeAddOp(v, OP_MemStore, iOffset, p->pLimit==0);
- VdbeComment((v, "# OFFSET counter"));
- addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iOffset, 0);
- sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
- sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
- sqlite3VdbeJumpHere(v, addr1);
- if( p->pLimit ){
- sqlite3VdbeAddOp(v, OP_Add, 0, 0);
- }
- }
- if( p->pLimit ){
- addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iLimit, 0);
- sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
- sqlite3VdbeAddOp(v, OP_MemInt, -1, iLimit+1);
- addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
- sqlite3VdbeJumpHere(v, addr1);
- sqlite3VdbeAddOp(v, OP_MemStore, iLimit+1, 1);
- VdbeComment((v, "# LIMIT+OFFSET"));
- sqlite3VdbeJumpHere(v, addr2);
- }
-}
-
-/*
-** Allocate a virtual index to use for sorting.
-*/
-static void createSortingIndex(Parse *pParse, Select *p, ExprList *pOrderBy){
- if( pOrderBy ){
- int addr;
- assert( pOrderBy->iECursor==0 );
- pOrderBy->iECursor = pParse->nTab++;
- addr = sqlite3VdbeAddOp(pParse->pVdbe, OP_OpenEphemeral,
- pOrderBy->iECursor, pOrderBy->nExpr+1);
- assert( p->addrOpenEphm[2] == -1 );
- p->addrOpenEphm[2] = addr;
- }
-}
-
-#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 */
-
-#ifndef SQLITE_OMIT_COMPOUND_SELECT
-/*
-** This routine is called to process a query that is really the union
-** or intersection of two or more separate queries.
-**
-** "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 */
- int eDest, /* \___ Store query results as specified */
- int iParm, /* / by these two parameters. */
- char *aff /* If eDest is SRT_Union, the affinity string */
-){
- int rc = SQLITE_OK; /* Success code from a subroutine */
- Select *pPrior; /* Another SELECT immediately to our left */
- Vdbe *v; /* Generate code to this VDBE */
- int nCol; /* Number of columns in the result set */
- ExprList *pOrderBy; /* The ORDER BY clause on p */
- int aSetP2[2]; /* Set P2 value of these op to number of columns */
- int nSetP2 = 0; /* Number of slots in aSetP2[] used */
-
- /* 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.
- */
- if( p==0 || p->pPrior==0 ){
- rc = 1;
- goto multi_select_end;
- }
- 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;
- }
-
- /* Make sure we have a valid query engine. If not, create a new one.
- */
- v = sqlite3GetVdbe(pParse);
- if( v==0 ){
- rc = 1;
- goto multi_select_end;
- }
-
- /* Create the destination temporary table if necessary
- */
- if( eDest==SRT_EphemTab ){
- assert( p->pEList );
- assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
- aSetP2[nSetP2++] = sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, 0);
- eDest = SRT_Table;
- }
-
- /* Generate code for the left and right SELECT statements.
- */
- pOrderBy = p->pOrderBy;
- switch( p->op ){
- case TK_ALL: {
- if( pOrderBy==0 ){
- int addr = 0;
- assert( !pPrior->pLimit );
- pPrior->pLimit = p->pLimit;
- pPrior->pOffset = p->pOffset;
- rc = sqlite3Select(pParse, pPrior, eDest, iParm, 0, 0, 0, aff);
- 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>=0 ){
- addr = sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, 0);
- VdbeComment((v, "# Jump ahead if LIMIT reached"));
- }
- rc = sqlite3Select(pParse, p, eDest, iParm, 0, 0, 0, aff);
- p->pPrior = pPrior;
- if( rc ){
- goto multi_select_end;
- }
- if( addr ){
- sqlite3VdbeJumpHere(v, addr);
- }
- break;
- }
- /* For UNION ALL ... ORDER BY fall through to the next case */
- }
- 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;
-
- priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
- if( eDest==priorOp && pOrderBy==0 && !p->pLimit && !p->pOffset ){
- /* We can reuse a temporary table generated by a SELECT to our
- ** right.
- */
- unionTab = iParm;
- }else{
- /* We will need to create our own temporary table to hold the
- ** intermediate results.
- */
- unionTab = pParse->nTab++;
- if( processCompoundOrderBy(pParse, p, unionTab) ){
- rc = 1;
- goto multi_select_end;
- }
- addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, unionTab, 0);
- if( priorOp==SRT_Table ){
- assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
- aSetP2[nSetP2++] = addr;
- }else{
- assert( p->addrOpenEphm[0] == -1 );
- p->addrOpenEphm[0] = addr;
- p->pRightmost->usesEphm = 1;
- }
- createSortingIndex(pParse, p, pOrderBy);
- assert( p->pEList );
- }
-
- /* Code the SELECT statements to our left
- */
- assert( !pPrior->pOrderBy );
- rc = sqlite3Select(pParse, pPrior, priorOp, unionTab, 0, 0, 0, aff);
- if( rc ){
- goto multi_select_end;
- }
-
- /* Code the current SELECT statement
- */
- switch( p->op ){
- case TK_EXCEPT: op = SRT_Except; break;
- case TK_UNION: op = SRT_Union; break;
- case TK_ALL: op = SRT_Table; break;
- }
- p->pPrior = 0;
- p->pOrderBy = 0;
- p->disallowOrderBy = pOrderBy!=0;
- pLimit = p->pLimit;
- p->pLimit = 0;
- pOffset = p->pOffset;
- p->pOffset = 0;
- rc = sqlite3Select(pParse, p, op, unionTab, 0, 0, 0, aff);
- /* Query flattening in sqlite3Select() might refill p->pOrderBy.
- ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
- sqlite3ExprListDelete(p->pOrderBy);
- p->pPrior = pPrior;
- p->pOrderBy = pOrderBy;
- sqlite3ExprDelete(p->pLimit);
- p->pLimit = pLimit;
- p->pOffset = pOffset;
- p->iLimit = -1;
- p->iOffset = -1;
- if( rc ){
- goto multi_select_end;
- }
-
-
- /* Convert the data in the temporary table into whatever form
- ** it is that we currently need.
- */
- if( eDest!=priorOp || unionTab!=iParm ){
- int iCont, iBreak, iStart;
- assert( p->pEList );
- if( 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);
- sqlite3VdbeAddOp(v, OP_Rewind, unionTab, iBreak);
- iStart = sqlite3VdbeCurrentAddr(v);
- rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
- pOrderBy, -1, eDest, iParm,
- iCont, iBreak, 0);
- if( rc ){
- rc = 1;
- goto multi_select_end;
- }
- sqlite3VdbeResolveLabel(v, iCont);
- sqlite3VdbeAddOp(v, OP_Next, unionTab, iStart);
- sqlite3VdbeResolveLabel(v, iBreak);
- sqlite3VdbeAddOp(v, OP_Close, unionTab, 0);
- }
- break;
- }
- case TK_INTERSECT: {
- int tab1, tab2;
- int iCont, iBreak, iStart;
- Expr *pLimit, *pOffset;
- int addr;
-
- /* 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++;
- if( processCompoundOrderBy(pParse, p, tab1) ){
- rc = 1;
- goto multi_select_end;
- }
- createSortingIndex(pParse, p, pOrderBy);
-
- addr = sqlite3VdbeAddOp(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".
- */
- rc = sqlite3Select(pParse, pPrior, SRT_Union, tab1, 0, 0, 0, aff);
- if( rc ){
- goto multi_select_end;
- }
-
- /* Code the current SELECT into temporary table "tab2"
- */
- addr = sqlite3VdbeAddOp(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;
- rc = sqlite3Select(pParse, p, SRT_Union, tab2, 0, 0, 0, aff);
- p->pPrior = pPrior;
- sqlite3ExprDelete(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( 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);
- sqlite3VdbeAddOp(v, OP_Rewind, tab1, iBreak);
- iStart = sqlite3VdbeAddOp(v, OP_RowKey, tab1, 0);
- sqlite3VdbeAddOp(v, OP_NotFound, tab2, iCont);
- rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
- pOrderBy, -1, eDest, iParm,
- iCont, iBreak, 0);
- if( rc ){
- rc = 1;
- goto multi_select_end;
- }
- sqlite3VdbeResolveLabel(v, iCont);
- sqlite3VdbeAddOp(v, OP_Next, tab1, iStart);
- sqlite3VdbeResolveLabel(v, iBreak);
- sqlite3VdbeAddOp(v, OP_Close, tab2, 0);
- sqlite3VdbeAddOp(v, OP_Close, tab1, 0);
- break;
- }
- }
-
- /* 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;
- }
-
- /* Set the number of columns in temporary tables
- */
- nCol = p->pEList->nExpr;
- while( nSetP2 ){
- sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
- }
-
- /* Compute collating sequences used by either the ORDER BY clause or
- ** by any temporary tables needed to implement the compound select.
- ** Attach the KeyInfo structure to all temporary tables. Invoke the
- ** ORDER BY processing if there is an ORDER BY clause.
- **
- ** 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( pOrderBy || p->usesEphm ){
- int i; /* Loop counter */
- KeyInfo *pKeyInfo; /* Collating sequence for the result set */
- Select *pLoop; /* For looping through SELECT statements */
- int nKeyCol; /* Number of entries in pKeyInfo->aCol[] */
- CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
- CollSeq **aCopy; /* A copy of pKeyInfo->aColl[] */
-
- assert( p->pRightmost==p );
- nKeyCol = nCol + (pOrderBy ? pOrderBy->nExpr : 0);
- pKeyInfo = (KeyInfo*)sqlite3DbMallocZero(pParse->db,
- sizeof(*pKeyInfo)+nKeyCol*(sizeof(CollSeq*) + 1));
- if( !pKeyInfo ){
- rc = SQLITE_NOMEM;
- goto multi_select_end;
- }
-
- pKeyInfo->enc = ENC(pParse->db);
- pKeyInfo->nField = nCol;
-
- for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
- *apColl = multiSelectCollSeq(pParse, p, i);
- if( 0==*apColl ){
- *apColl = pParse->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);
- sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO);
- pLoop->addrOpenEphm[i] = -1;
- }
- }
-
- if( pOrderBy ){
- ExprList::ExprList_item *pOTerm = pOrderBy->a;
- int nOrderByExpr = pOrderBy->nExpr;
- int addr;
- u8 *pSortOrder;
-
- /* Reuse the same pKeyInfo for the ORDER BY as was used above for
- ** the compound select statements. Except we have to change out the
- ** pKeyInfo->aColl[] values. Some of the aColl[] values will be
- ** reused when constructing the pKeyInfo for the ORDER BY, so make
- ** a copy. Sufficient space to hold both the nCol entries for
- ** the compound select and the nOrderbyExpr entries for the ORDER BY
- ** was allocated above. But we need to move the compound select
- ** entries out of the way before constructing the ORDER BY entries.
- ** Move the compound select entries into aCopy[] where they can be
- ** accessed and reused when constructing the ORDER BY entries.
- ** Because nCol might be greater than or less than nOrderByExpr
- ** we have to use memmove() when doing the copy.
- */
- aCopy = &pKeyInfo->aColl[nOrderByExpr];
- pSortOrder = pKeyInfo->aSortOrder = (u8*)&aCopy[nCol];
- memmove(aCopy, pKeyInfo->aColl, nCol*sizeof(CollSeq*));
-
- apColl = pKeyInfo->aColl;
- for(i=0; i<nOrderByExpr; i++, pOTerm++, apColl++, pSortOrder++){
- Expr *pExpr = pOTerm->pExpr;
- if( (pExpr->flags & EP_ExpCollate) ){
- assert( pExpr->pColl!=0 );
- *apColl = pExpr->pColl;
- }else{
- *apColl = aCopy[pExpr->iColumn];
- }
- *pSortOrder = pOTerm->sortOrder;
- }
- assert( p->pRightmost==p );
- assert( p->addrOpenEphm[2]>=0 );
- addr = p->addrOpenEphm[2];
- sqlite3VdbeChangeP2(v, addr, p->pOrderBy->nExpr+2);
- pKeyInfo->nField = nOrderByExpr;
- sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
- pKeyInfo = 0;
- generateSortTail(pParse, p, v, p->pEList->nExpr, eDest, iParm);
- }
-
- sqlite3_free(pKeyInfo);
- }
-
-multi_select_end:
- return rc;
-}
-#endif /* SQLITE_OMIT_COMPOUND_SELECT */
-
-#ifndef 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_VIEW) */
-
-#ifndef 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)
-**
-** 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(
- sqlite3 *db, /* Database connection */
- 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 */
-){
- Select *pSub; /* The inner query or "subquery" */
- 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 */
- SrcList::SrcList_item *pSubitem; /* The subquery */
-
- /* 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];
- 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) */
- }
-
- /* 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;
- }
-
- /* If we reach this point, it means flattening is permitted for the
- ** iFrom-th entry of the FROM clause in the outer query.
- */
-
- /* 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.
- */
- iParent = pSubitem->iCursor;
- {
- int nSubSrc = pSubSrc->nSrc;
- int jointype = pSubitem->jointype;
-
- sqlite3DeleteTable(pSubitem->pTab);
- sqlite3_free(pSubitem->zDatabase);
- sqlite3_free(pSubitem->zName);
- sqlite3_free(pSubitem->zAlias);
- pSubitem->pTab = 0;
- pSubitem->zDatabase = 0;
- pSubitem->zName = 0;
- pSubitem->zAlias = 0;
- if( nSubSrc>1 ){
- int extra = nSubSrc - 1;
- for(i=1; i<nSubSrc; i++){
- pSrc = sqlite3SrcListAppend(db, pSrc, 0, 0);
- if( pSrc==0 ){
- p->pSrc = 0;
- return 1;
- }
- }
- p->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 = p->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, p->pEList, iParent, pSub->pEList);
- if( isAgg ){
- substExprList(db, p->pGroupBy, iParent, pSub->pEList);
- substExpr(db, p->pHaving, iParent, pSub->pEList);
- }
- if( pSub->pOrderBy ){
- assert( p->pOrderBy==0 );
- p->pOrderBy = pSub->pOrderBy;
- pSub->pOrderBy = 0;
- }else if( p->pOrderBy ){
- substExprList(db, p->pOrderBy, iParent, pSub->pEList);
- }
- if( pSub->pWhere ){
- pWhere = sqlite3ExprDup(db, pSub->pWhere);
- }else{
- pWhere = 0;
- }
- if( subqueryIsAgg ){
- assert( p->pHaving==0 );
- p->pHaving = p->pWhere;
- p->pWhere = pWhere;
- substExpr(db, p->pHaving, iParent, pSub->pEList);
- p->pHaving = sqlite3ExprAnd(db, p->pHaving,
- sqlite3ExprDup(db, pSub->pHaving));
- assert( p->pGroupBy==0 );
- p->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy);
- }else{
- substExpr(db, p->pWhere, iParent, pSub->pEList);
- p->pWhere = sqlite3ExprAnd(db, p->pWhere, pWhere);
- }
-
- /* The flattened query is distinct if either the inner or the
- ** outer query is distinct.
- */
- p->isDistinct = p->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 ){
- p->pLimit = pSub->pLimit;
- pSub->pLimit = 0;
- }
-
- /* Finially, delete what is left of the subquery and return
- ** success.
- */
- sqlite3SelectDelete(pSub);
- return 1;
-}
-#endif /* SQLITE_OMIT_VIEW */
-
-/*
-** Analyze the SELECT statement passed in as an argument to see if it
-** is a simple min() or max() query. If it is and this query can be
-** satisfied using a single seek to the beginning or end of an index,
-** then generate the code for this SELECT and return 1. If this is not a
-** simple min() or max() query, then return 0;
-**
-** A simply min() or max() query looks like this:
-**
-** SELECT min(a) FROM table;
-** SELECT max(a) FROM table;
-**
-** The query may have only a single table in its FROM argument. There
-** can be no GROUP BY or HAVING or WHERE clauses. The result set must
-** be the min() or max() of a single column of the table. The column
-** in the min() or max() function must be indexed.
-**
-** The parameters to this routine are the same as for sqlite3Select().
-** See the header comment on that routine for additional information.
-*/
-static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){
- Expr *pExpr;
- int iCol;
- Table *pTab;
- Index *pIdx;
- int base;
- Vdbe *v;
- int seekOp;
- ExprList *pEList, *pList, eList;
- ExprList::ExprList_item eListItem;
- SrcList *pSrc;
- int brk;
- int iDb;
-
- /* Check to see if this query is a simple min() or max() query. Return
- ** zero if it is not.
- */
- if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
- pSrc = p->pSrc;
- if( pSrc->nSrc!=1 ) return 0;
- pEList = p->pEList;
- if( pEList->nExpr!=1 ) return 0;
- pExpr = pEList->a[0].pExpr;
- if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
- pList = pExpr->pList;
- if( pList==0 || pList->nExpr!=1 ) return 0;
- if( pExpr->token.n!=3 ) return 0;
- if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
- seekOp = OP_Rewind;
- }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
- seekOp = OP_Last;
- }else{
- return 0;
- }
- pExpr = pList->a[0].pExpr;
- if( pExpr->op!=TK_COLUMN ) return 0;
- iCol = pExpr->iColumn;
- pTab = pSrc->a[0].pTab;
-
- /* This optimization cannot be used with virtual tables. */
- if( IsVirtual(pTab) ) return 0;
-
- /* If we get to here, it means the query is of the correct form.
- ** Check to make sure we have an index and make pIdx point to the
- ** appropriate index. If the min() or max() is on an INTEGER PRIMARY
- ** key column, no index is necessary so set pIdx to NULL. If no
- ** usable index is found, return 0.
- */
- if( iCol<0 ){
- pIdx = 0;
- }else{
- CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
- if( pColl==0 ) return 0;
- for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
- assert( pIdx->nColumn>=1 );
- if( pIdx->aiColumn[0]==iCol &&
- 0==sqlite3StrICmp(pIdx->azColl[0], pColl->zName) ){
- break;
- }
- }
- if( pIdx==0 ) return 0;
- }
-
- /* Identify column types if we will be using the callback. This
- ** step is skipped if the output is going to a table or a memory cell.
- ** The column names have already been generated in the calling function.
- */
- v = sqlite3GetVdbe(pParse);
- if( v==0 ) return 0;
-
- /* If the output is destined for a temporary table, open that table.
- */
- if( eDest==SRT_EphemTab ){
- sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, 1);
- }
-
- /* Generating code to find the min or the max. Basically all we have
- ** to do is find the first or the last entry in the chosen index. If
- ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
- ** or last entry in the main table.
- */
- iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
- assert( iDb>=0 || pTab->isEphem );
- sqlite3CodeVerifySchema(pParse, iDb);
- sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
- base = pSrc->a[0].iCursor;
- brk = sqlite3VdbeMakeLabel(v);
- computeLimitRegisters(pParse, p, brk);
- if( pSrc->a[0].pSelect==0 ){
- sqlite3OpenTable(pParse, base, iDb, pTab, OP_OpenRead);
- }
- if( pIdx==0 ){
- sqlite3VdbeAddOp(v, seekOp, base, 0);
- }else{
- /* Even though the cursor used to open the index here is closed
- ** as soon as a single value has been read from it, allocate it
- ** using (pParse->nTab++) to prevent the cursor id from being
- ** reused. This is important for statements of the form
- ** "INSERT INTO x SELECT max() FROM x".
- */
- int iIdx;
- KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
- iIdx = pParse->nTab++;
- assert( pIdx->pSchema==pTab->pSchema );
- sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
- sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum,
- (char*)pKey, P3_KEYINFO_HANDOFF);
- if( seekOp==OP_Rewind ){
- sqlite3VdbeAddOp(v, OP_Null, 0, 0);
- sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
- seekOp = OP_MoveGt;
- }
- if( pIdx->aSortOrder[0]==SQLITE_SO_DESC ){
- /* Ticket #2514: invert the seek operator if we are using
- ** a descending index. */
- if( seekOp==OP_Last ){
- seekOp = OP_Rewind;
- }else{
- assert( seekOp==OP_MoveGt );
- seekOp = OP_MoveLt;
- }
- }
- sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
- sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);
- sqlite3VdbeAddOp(v, OP_Close, iIdx, 0);
- sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
- }
- eList.nExpr = 1;
- memset(&eListItem, 0, sizeof(eListItem));
- eList.a = &eListItem;
- eList.a[0].pExpr = pExpr;
- selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, brk, brk, 0);
- sqlite3VdbeResolveLabel(v, brk);
- sqlite3VdbeAddOp(v, OP_Close, base, 0);
-
- return 1;
-}
-
-/*
-** 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 ){
- ExprList::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=0;
- AggInfo::AggInfo_func *pFunc;
- if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
- return;
- }
- for(i=0; i<pAggInfo->nColumn; i++){
- sqlite3VdbeAddOp(v, OP_MemNull, pAggInfo->aCol[i].iMem, 0);
- }
- for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
- sqlite3VdbeAddOp(v, OP_MemNull, pFunc->iMem, 0);
- 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);
- sqlite3VdbeOp3(v, OP_OpenEphemeral, pFunc->iDistinct, 0,
- (char*)pKeyInfo, P3_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;
- AggInfo::AggInfo_func *pF;
- for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
- ExprList *pList = pF->pExpr->pList;
- sqlite3VdbeOp3(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0,
- (const char*)pF->pFunc, P3_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;
- AggInfo::AggInfo_func *pF;
- AggInfo::AggInfo_col *pC;
-
- pAggInfo->directMode = 1;
- for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
- int nArg;
- int addrNext = 0;
- ExprList *pList = pF->pExpr->pList;
- if( pList ){
- nArg = pList->nExpr;
- sqlite3ExprCodeExprList(pParse, pList);
- }else{
- nArg = 0;
- }
- if( pF->iDistinct>=0 ){
- addrNext = sqlite3VdbeMakeLabel(v);
- assert( nArg==1 );
- codeDistinct(v, pF->iDistinct, addrNext, 1);
- }
- if( pF->pFunc->needCollSeq ){
- CollSeq *pColl = 0;
- ExprList::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;
- }
- sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
- }
- sqlite3VdbeOp3(v, OP_AggStep, pF->iMem, nArg, (const char*)pF->pFunc, P3_FUNCDEF);
- if( addrNext ){
- sqlite3VdbeResolveLabel(v, addrNext);
- }
- }
- for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
- sqlite3ExprCode(pParse, pC->pExpr);
- sqlite3VdbeAddOp(v, OP_MemStore, pC->iMem, 1);
- }
- pAggInfo->directMode = 0;
-}
-
-
-/*
-** Generate code for the given SELECT statement.
-**
-** The results are distributed in various ways depending on the
-** value of eDest and iParm.
-**
-** eDest Value Result
-** ------------ -------------------------------------------
-** SRT_Callback Invoke the callback for each row of the result.
-**
-** SRT_Mem Store first result in memory cell iParm
-**
-** SRT_Set Store results as keys of table iParm.
-**
-** SRT_Union Store results as a key in a temporary table iParm
-**
-** SRT_Except Remove results from the temporary table iParm.
-**
-** SRT_Table Store results in temporary table iParm
-**
-** The table above is incomplete. Additional eDist value have be added
-** since this comment was written. See the selectInnerLoop() function for
-** a complete 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. */
- int eDest, /* How to dispose of the results */
- int iParm, /* A parameter used by the eDest disposal method */
- 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 */
- char *aff /* If eDest is SRT_Union, the affinity string */
-){
- 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(eDest) ){
- p->pOrderBy = 0;
- }
- if( sqlite3SelectResolve(pParse, p, 0) ){
- goto select_end;
- }
- p->pOrderBy = pOrderBy;
-
-#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;
- for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
- pLoop->pRightmost = p;
- pLoop->pNext = pRight;
- pRight = pLoop;
- }
- if( SQLITE_MAX_COMPOUND_SELECT>0 && cnt>SQLITE_MAX_COMPOUND_SELECT ){
- sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
- return 1;
- }
- }
- return multiSelect(pParse, p, eDest, iParm, aff);
- }
-#endif
-
- /* Make local copies of the parameters for this query.
- */
- pTabList = p->pSrc;
- pWhere = p->pWhere;
- pGroupBy = p->pGroupBy;
- pHaving = p->pHaving;
- isAgg = p->isAgg;
- isDistinct = p->isDistinct;
- 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;
-
- /* If writing to memory or generating a set
- ** only a single column may be output.
- */
-#ifndef SQLITE_OMIT_SUBQUERY
- if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
- goto select_end;
- }
-#endif
-
- /* ORDER BY is ignored for some destinations.
- */
- if( IgnorableOrderby(eDest) ){
- 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; i<pTabList->nSrc; i++){
- const char *zSavedAuthContext = 0;
- int needRestoreContext;
- SrcList::SrcList_item *pItem = &pTabList->a[i];
-
- if( pItem->pSelect==0 || pItem->isPopulated ) continue;
- if( pItem->zName!=0 ){
- zSavedAuthContext = pParse->zAuthContext;
- pParse->zAuthContext = pItem->zName;
- needRestoreContext = 1;
- }else{
- needRestoreContext = 0;
- }
-#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
- /* 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);
-#endif
- sqlite3Select(pParse, pItem->pSelect, SRT_EphemTab,
- pItem->iCursor, p, i, &isAgg, 0);
- if( db->mallocFailed ){
- goto select_end;
- }
-#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
- pParse->nHeight -= sqlite3SelectExprHeight(p);
-#endif
- if( needRestoreContext ){
- pParse->zAuthContext = zSavedAuthContext;
- }
- pTabList = p->pSrc;
- pWhere = p->pWhere;
- if( !IgnorableOrderby(eDest) ){
- pOrderBy = p->pOrderBy;
- }
- pGroupBy = p->pGroupBy;
- pHaving = p->pHaving;
- isDistinct = p->isDistinct;
- }
-#endif
-
- /* Check for the special case of a min() or max() function by itself
- ** in the result set.
- */
- if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
- rc = 0;
- goto select_end;
- }
-
- /* Check to see if this is a subquery that can be "flattened" into its parent.
- ** If flattening is a possiblity, do so and return immediately.
- */
-#ifndef SQLITE_OMIT_VIEW
- if( pParent && pParentAgg &&
- flattenSubquery(db, pParent, parentTab, *pParentAgg, isAgg) ){
- if( isAgg ) *pParentAgg = 1;
- 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;
- if( pParse->nErr ){
- goto select_end;
- }
- pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
- pOrderBy->iECursor = pParse->nTab++;
- p->addrOpenEphm[2] = addrSortIndex =
- sqlite3VdbeOp3(v, OP_OpenEphemeral, pOrderBy->iECursor, pOrderBy->nExpr+2, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
- }else{
- addrSortIndex = -1;
- }
-
- /* If the output is destined for a temporary table, open that table.
- */
- if( eDest==SRT_EphemTab ){
- sqlite3VdbeAddOp(v, OP_OpenEphemeral, 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);
- sqlite3VdbeOp3(v, OP_OpenEphemeral, distinct, 0,
- (char*)pKeyInfo, P3_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);
- 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);
- if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, eDest,
- iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
- goto select_end;
- }
-
- /* 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 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 addrGroupByChange; /* Code that runs when any GROUP BY term changes */
- int addrProcessRow; /* Code to process a single input row */
- int addrEnd; /* End of all processing */
- int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
- int addrReset; /* Subroutine for resetting the accumulator */
-
- 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;
- if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
- goto select_end;
- }
- if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
- goto select_end;
- }
- if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
- goto select_end;
- }
- sAggInfo.nAccumulator = sAggInfo.nColumn;
- for(i=0; i<sAggInfo.nFunc; i++){
- if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
- goto select_end;
- }
- }
- 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 */
-
- /* Create labels that we will be needing
- */
-
- addrInitializeLoop = sqlite3VdbeMakeLabel(v);
- addrGroupByChange = sqlite3VdbeMakeLabel(v);
- addrProcessRow = 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 =
- sqlite3VdbeOp3(v, OP_OpenEphemeral, sAggInfo.sortingIdx,
- sAggInfo.nSortingColumn,
- (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
-
- /* Initialize memory locations used by GROUP BY aggregate processing
- */
- iUseFlag = pParse->nMem++;
- iAbortFlag = pParse->nMem++;
- iAMem = pParse->nMem;
- pParse->nMem += pGroupBy->nExpr;
- iBMem = pParse->nMem;
- pParse->nMem += pGroupBy->nExpr;
- sqlite3VdbeAddOp(v, OP_MemInt, 0, iAbortFlag);
- VdbeComment((v, "# clear abort flag"));
- sqlite3VdbeAddOp(v, OP_MemInt, 0, iUseFlag);
- VdbeComment((v, "# indicate accumulator empty"));
- sqlite3VdbeAddOp(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);
- sqlite3VdbeAddOp(v, OP_MemInt, 1, iAbortFlag);
- VdbeComment((v, "# set abort flag"));
- sqlite3VdbeAddOp(v, OP_Return, 0, 0);
- addrOutputRow = sqlite3VdbeCurrentAddr(v);
- sqlite3VdbeAddOp(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
- VdbeComment((v, "# Groupby result generator entry point"));
- sqlite3VdbeAddOp(v, OP_Return, 0, 0);
- finalizeAggFunctions(pParse, &sAggInfo);
- if( pHaving ){
- sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, 1);
- }
- rc = selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
- distinct, eDest, iParm,
- addrOutputRow+1, addrSetAbort, aff);
- if( rc ){
- goto select_end;
- }
- sqlite3VdbeAddOp(v, OP_Return, 0, 0);
- VdbeComment((v, "# end groupby result generator"));
-
- /* Generate a subroutine that will reset the group-by accumulator
- */
- addrReset = sqlite3VdbeCurrentAddr(v);
- resetAccumulator(pParse, &sAggInfo);
- sqlite3VdbeAddOp(v, OP_Return, 0, 0);
-
- /* 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);
- sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
- pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy);
- 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
- */
- groupBySort = 1;
- sqlite3ExprCodeExprList(pParse, pGroupBy);
- sqlite3VdbeAddOp(v, OP_Sequence, sAggInfo.sortingIdx, 0);
- j = pGroupBy->nExpr+1;
- for(i=0; i<sAggInfo.nColumn; i++){
- AggInfo::AggInfo_col *pCol = &sAggInfo.aCol[i];
- if( pCol->iSorterColumn<j ) continue;
- sqlite3ExprCodeGetColumn(v, pCol->pTab, pCol->iColumn, pCol->iTable);
- j++;
- }
- sqlite3VdbeAddOp(v, OP_MakeRecord, j, 0);
- sqlite3VdbeAddOp(v, OP_IdxInsert, sAggInfo.sortingIdx, 0);
- sqlite3WhereEnd(pWInfo);
- sqlite3VdbeAddOp(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 ){
- sqlite3VdbeAddOp(v, OP_Column, sAggInfo.sortingIdx, j);
- }else{
- sAggInfo.directMode = 1;
- sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr);
- }
- sqlite3VdbeAddOp(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
- }
- for(j=pGroupBy->nExpr-1; j>=0; j--){
- if( j<pGroupBy->nExpr-1 ){
- sqlite3VdbeAddOp(v, OP_MemLoad, iBMem+j, 0);
- }
- sqlite3VdbeAddOp(v, OP_MemLoad, iAMem+j, 0);
- if( j==0 ){
- sqlite3VdbeAddOp(v, OP_Eq, 0x200, addrProcessRow);
- }else{
- sqlite3VdbeAddOp(v, OP_Ne, 0x200, addrGroupByChange);
- }
- sqlite3VdbeChangeP3(v, -1, (const char*)pKeyInfo->aColl[j], P3_COLLSEQ);
- }
-
- /* Generate code that runs whenever the GROUP BY changes.
- ** Change 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.
- */
- sqlite3VdbeResolveLabel(v, addrGroupByChange);
- for(j=0; j<pGroupBy->nExpr; j++){
- sqlite3VdbeAddOp(v, OP_MemMove, iAMem+j, iBMem+j);
- }
- sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
- VdbeComment((v, "# output one row"));
- sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
- VdbeComment((v, "# check abort flag"));
- sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
- VdbeComment((v, "# reset accumulator"));
-
- /* Update the aggregate accumulators based on the content of
- ** the current row
- */
- sqlite3VdbeResolveLabel(v, addrProcessRow);
- updateAccumulator(pParse, &sAggInfo);
- sqlite3VdbeAddOp(v, OP_MemInt, 1, iUseFlag);
- VdbeComment((v, "# indicate data in accumulator"));
-
- /* End of the loop
- */
- if( groupBySort ){
- sqlite3VdbeAddOp(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
- }else{
- sqlite3WhereEnd(pWInfo);
- sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
- }
-
- /* Output the final row of result
- */
- sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
- VdbeComment((v, "# output final row"));
-
- } /* endif pGroupBy */
- else {
- /* 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, 0);
- if( pWInfo==0 ) goto select_end;
- updateAccumulator(pParse, &sAggInfo);
- sqlite3WhereEnd(pWInfo);
- finalizeAggFunctions(pParse, &sAggInfo);
- pOrderBy = 0;
- if( pHaving ){
- sqlite3ExprIfFalse(pParse, pHaving, addrEnd, 1);
- }
- selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1,
- eDest, iParm, addrEnd, addrEnd, aff);
- }
- 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, eDest, iParm);
- }
-
-#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 && eDest==SRT_Callback ){
- generateColumnNames(pParse, pTabList, pEList);
- }
-
- sqlite3_free(sAggInfo.aCol);
- sqlite3_free(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) */