diff -r 87e863f6f840 -r 3903521a36da engine/sqlite/src/select.cpp --- 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; jn==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; inCol; 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; inSrc-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; jnCol; 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; jnId; 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; inExpr; - 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; ipExpr); - 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; iiLimit>=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;jnSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++); - if( jnSrc ){ - 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 && iColpEList->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 && iColnCol) ); - 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; inExpr; 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; inExpr; 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; jnSrc && pTabList->a[j].iCursor!=p->iTable; j++){} - assert( jnSrc ); - pTab = pTabList->a[j].pTab; - if( iCol<0 ) iCol = pTab->iPKey; - assert( iCol==-1 || (iCol>=0 && iColnCol) ); - 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; inCol; 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 " phrase, use 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; jzName = 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; inSrc; 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; knExpr; 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( knExpr ){ - /* - ** 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; knExpr; 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; inSrc; 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; jnCol; 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; inExpr; 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; inExpr; 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; inExpr; 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; inExpr; i++){ - pOrderBy->a[i].done = 0; - } - while( pSelect->pPrior ){ - pSelect = pSelect->pPrior; - } - while( pSelect && moreToDo ){ - moreToDo = 0; - for(i=0; inExpr; 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; inExpr; 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( nSetP2pOrderBy; - 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( nSetP2addrOpenEphm[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; idb->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; ipExpr; - 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->iColumnnExpr ); - 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; inExpr; 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 && iFromnSrc ); - 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; ipSrc = 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; ia[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; inExpr; 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; inExpr; 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; inExpr; 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; inColumn; i++){ - sqlite3VdbeAddOp(v, OP_MemNull, pAggInfo->aCol[i].iMem, 0); - } - for(pFunc=pAggInfo->aFunc, i=0; inFunc; 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; inFunc; 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; inFunc; 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 && jpExpr); - } - 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; inAccumulator; 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; inSrc; 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; ipList) ){ - 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; iiSorterColumnpTab, 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; jnExpr; 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, jnExpr-1); - } - for(j=pGroupBy->nExpr-1; j>=0; j--){ - if( jnExpr-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; jnExpr; 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; inExpr; i++){ - sqlite3PrintExpr(pList->a[i].pExpr); - if( inExpr-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; ipSrc->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( ipSrc->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) */