drh
1333 lines
42 KiB
C
1333 lines
42 KiB
C
/*
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** 2001 September 15
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This file contains C code routines that are called by the parser
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** to handle SELECT statements in SQLite.
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**
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** $Id: select.c,v 1.70 2002/02/28 01:46:13 drh Exp $
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*/
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#include "sqliteInt.h"
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/*
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** Allocate a new Select structure and return a pointer to that
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** structure.
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*/
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Select *sqliteSelectNew(
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ExprList *pEList, /* which columns to include in the result */
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IdList *pSrc, /* the FROM clause -- which tables to scan */
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Expr *pWhere, /* the WHERE clause */
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ExprList *pGroupBy, /* the GROUP BY clause */
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Expr *pHaving, /* the HAVING clause */
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ExprList *pOrderBy, /* the ORDER BY clause */
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int isDistinct, /* true if the DISTINCT keyword is present */
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int nLimit, /* LIMIT value. -1 means not used */
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int nOffset /* OFFSET value. -1 means not used */
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){
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Select *pNew;
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pNew = sqliteMalloc( sizeof(*pNew) );
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if( pNew==0 ){
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sqliteExprListDelete(pEList);
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sqliteIdListDelete(pSrc);
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sqliteExprDelete(pWhere);
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sqliteExprListDelete(pGroupBy);
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sqliteExprDelete(pHaving);
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sqliteExprListDelete(pOrderBy);
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}else{
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pNew->pEList = pEList;
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pNew->pSrc = pSrc;
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pNew->pWhere = pWhere;
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pNew->pGroupBy = pGroupBy;
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pNew->pHaving = pHaving;
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pNew->pOrderBy = pOrderBy;
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pNew->isDistinct = isDistinct;
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pNew->op = TK_SELECT;
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pNew->nLimit = nLimit;
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pNew->nOffset = nOffset;
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}
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return pNew;
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}
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/*
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** Delete the given Select structure and all of its substructures.
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*/
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void sqliteSelectDelete(Select *p){
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if( p==0 ) return;
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sqliteExprListDelete(p->pEList);
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sqliteIdListDelete(p->pSrc);
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sqliteExprDelete(p->pWhere);
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sqliteExprListDelete(p->pGroupBy);
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sqliteExprDelete(p->pHaving);
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sqliteExprListDelete(p->pOrderBy);
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sqliteSelectDelete(p->pPrior);
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sqliteFree(p->zSelect);
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sqliteFree(p);
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}
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/*
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** Delete the aggregate information from the parse structure.
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*/
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static void sqliteAggregateInfoReset(Parse *pParse){
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sqliteFree(pParse->aAgg);
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pParse->aAgg = 0;
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pParse->nAgg = 0;
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pParse->useAgg = 0;
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}
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/*
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** This routine generates the code for the inside of the inner loop
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** of a SELECT.
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**
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** The pEList is used to determine the values for each column in the
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** result row. Except if pEList==NULL, then we just read nColumn
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** elements from the srcTab table.
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*/
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static int selectInnerLoop(
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Parse *pParse, /* The parser context */
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ExprList *pEList, /* List of values being extracted */
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int srcTab, /* Pull data from this table */
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int nColumn, /* Number of columns in the source table */
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ExprList *pOrderBy, /* If not NULL, sort results using this key */
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int distinct, /* If >=0, make sure results are distinct */
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int eDest, /* How to dispose of the results */
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int iParm, /* An argument to the disposal method */
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int iContinue, /* Jump here to continue with next row */
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int iBreak /* Jump here to break out of the inner loop */
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){
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Vdbe *v = pParse->pVdbe;
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int i;
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if( v==0 ) return 0;
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/* Pull the requested columns.
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*/
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if( pEList ){
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for(i=0; i<pEList->nExpr; i++){
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sqliteExprCode(pParse, pEList->a[i].pExpr);
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}
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nColumn = pEList->nExpr;
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}else{
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for(i=0; i<nColumn; i++){
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sqliteVdbeAddOp(v, OP_Column, srcTab, i);
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}
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}
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/* If the DISTINCT keyword was present on the SELECT statement
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** and this row has been seen before, then do not make this row
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** part of the result.
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*/
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if( distinct>=0 ){
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int lbl = sqliteVdbeMakeLabel(v);
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sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1);
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sqliteVdbeAddOp(v, OP_Distinct, distinct, lbl);
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sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
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sqliteVdbeAddOp(v, OP_Goto, 0, iContinue);
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sqliteVdbeResolveLabel(v, lbl);
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sqliteVdbeAddOp(v, OP_String, 0, 0);
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sqliteVdbeAddOp(v, OP_PutStrKey, distinct, 0);
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}
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/* If there is an ORDER BY clause, then store the results
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** in a sorter.
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*/
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if( pOrderBy ){
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char *zSortOrder;
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sqliteVdbeAddOp(v, OP_SortMakeRec, nColumn, 0);
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zSortOrder = sqliteMalloc( pOrderBy->nExpr + 1 );
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if( zSortOrder==0 ) return 1;
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for(i=0; i<pOrderBy->nExpr; i++){
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zSortOrder[i] = pOrderBy->a[i].sortOrder ? '-' : '+';
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sqliteExprCode(pParse, pOrderBy->a[i].pExpr);
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}
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zSortOrder[pOrderBy->nExpr] = 0;
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sqliteVdbeAddOp(v, OP_SortMakeKey, pOrderBy->nExpr, 0);
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sqliteVdbeChangeP3(v, -1, zSortOrder, strlen(zSortOrder));
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sqliteFree(zSortOrder);
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sqliteVdbeAddOp(v, OP_SortPut, 0, 0);
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}else
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/* In this mode, write each query result to the key of the temporary
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** table iParm.
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*/
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if( eDest==SRT_Union ){
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sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
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sqliteVdbeAddOp(v, OP_String, iParm, 0);
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sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
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}else
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/* Store the result as data using a unique key.
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*/
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if( eDest==SRT_Table ){
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sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
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sqliteVdbeAddOp(v, OP_NewRecno, iParm, 0);
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sqliteVdbeAddOp(v, OP_Pull, 1, 0);
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sqliteVdbeAddOp(v, OP_PutIntKey, iParm, 0);
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}else
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/* Construct a record from the query result, but instead of
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** saving that record, use it as a key to delete elements from
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** the temporary table iParm.
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*/
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if( eDest==SRT_Except ){
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int addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
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sqliteVdbeAddOp(v, OP_NotFound, iParm, addr+3);
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sqliteVdbeAddOp(v, OP_Delete, iParm, 0);
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}else
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/* If we are creating a set for an "expr IN (SELECT ...)" construct,
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** then there should be a single item on the stack. Write this
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** item into the set table with bogus data.
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*/
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if( eDest==SRT_Set ){
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assert( nColumn==1 );
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sqliteVdbeAddOp(v, OP_String, 0, 0);
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sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
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}else
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/* If this is a scalar select that is part of an expression, then
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** store the results in the appropriate memory cell and break out
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** of the scan loop.
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*/
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if( eDest==SRT_Mem ){
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assert( nColumn==1 );
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sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
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sqliteVdbeAddOp(v, OP_Goto, 0, iBreak);
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}else
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/* If none of the above, send the data to the callback function.
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*/
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{
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sqliteVdbeAddOp(v, OP_Callback, nColumn, iBreak);
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}
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return 0;
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}
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/*
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** If the inner loop was generated using a non-null pOrderBy argument,
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** then the results were placed in a sorter. After the loop is terminated
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** we need to run the sorter and output the results. The following
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** routine generates the code needed to do that.
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*/
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static void generateSortTail(Vdbe *v, int nColumn){
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int end = sqliteVdbeMakeLabel(v);
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int addr;
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sqliteVdbeAddOp(v, OP_Sort, 0, 0);
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addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end);
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sqliteVdbeAddOp(v, OP_SortCallback, nColumn, end);
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sqliteVdbeAddOp(v, OP_Goto, 0, addr);
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sqliteVdbeResolveLabel(v, end);
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sqliteVdbeAddOp(v, OP_SortReset, 0, 0);
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}
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/*
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** Generate code that will tell the VDBE how many columns there
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** are in the result and the name for each column. This information
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** is used to provide "argc" and "azCol[]" values in the callback.
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*/
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static
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void generateColumnNames(Parse *pParse, IdList *pTabList, ExprList *pEList){
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Vdbe *v = pParse->pVdbe;
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int i;
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if( pParse->colNamesSet || v==0 || sqlite_malloc_failed ) return;
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pParse->colNamesSet = 1;
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sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0);
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for(i=0; i<pEList->nExpr; i++){
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Expr *p;
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int showFullNames;
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if( pEList->a[i].zName ){
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char *zName = pEList->a[i].zName;
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sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
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sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
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continue;
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}
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p = pEList->a[i].pExpr;
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if( p==0 ) continue;
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showFullNames = (pParse->db->flags & SQLITE_FullColNames)!=0;
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if( p->span.z && p->span.z[0] && !showFullNames ){
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int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, 0);
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sqliteVdbeChangeP3(v, -1, p->span.z, p->span.n);
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sqliteVdbeCompressSpace(v, addr);
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}else if( p->op==TK_COLUMN && pTabList ){
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Table *pTab = pTabList->a[p->iTable - pParse->nTab].pTab;
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char *zCol;
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int iCol = p->iColumn;
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if( iCol<0 ) iCol = pTab->iPKey;
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assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
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zCol = iCol<0 ? "_ROWID_" : pTab->aCol[iCol].zName;
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if( pTabList->nId>1 || showFullNames ){
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char *zName = 0;
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char *zTab;
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zTab = pTabList->a[p->iTable - pParse->nTab].zAlias;
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if( showFullNames || zTab==0 ) zTab = pTab->zName;
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sqliteSetString(&zName, zTab, ".", zCol, 0);
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sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
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sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
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sqliteFree(zName);
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}else{
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sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
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sqliteVdbeChangeP3(v, -1, zCol, 0);
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}
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}else if( p->span.z && p->span.z[0] ){
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int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, 0);
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sqliteVdbeChangeP3(v, -1, p->span.z, p->span.n);
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sqliteVdbeCompressSpace(v, addr);
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}else{
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char zName[30];
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assert( p->op!=TK_COLUMN || pTabList==0 );
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sprintf(zName, "column%d", i+1);
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sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
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sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
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}
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}
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}
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/*
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** Name of the connection operator, used for error messages.
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*/
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static const char *selectOpName(int id){
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char *z;
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switch( id ){
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case TK_ALL: z = "UNION ALL"; break;
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case TK_INTERSECT: z = "INTERSECT"; break;
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case TK_EXCEPT: z = "EXCEPT"; break;
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default: z = "UNION"; break;
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}
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return z;
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}
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/*
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** Given a SELECT statement, generate a Table structure that describes
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** the result set of that SELECT.
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*/
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Table *sqliteResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
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Table *pTab;
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int i;
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ExprList *pEList;
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static int fillInColumnList(Parse*, Select*);
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if( fillInColumnList(pParse, pSelect) ){
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return 0;
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}
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pTab = sqliteMalloc( sizeof(Table) );
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if( pTab==0 ){
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return 0;
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}
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pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
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pEList = pSelect->pEList;
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pTab->nCol = pEList->nExpr;
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pTab->aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
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for(i=0; i<pTab->nCol; i++){
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Expr *p;
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if( pEList->a[i].zName ){
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pTab->aCol[i].zName = sqliteStrDup(pEList->a[i].zName);
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}else if( (p=pEList->a[i].pExpr)->span.z && p->span.z[0] ){
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sqliteSetNString(&pTab->aCol[i].zName, p->span.z, p->span.n, 0);
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}else if( p->op==TK_DOT && p->pRight && p->pRight->token.z &&
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p->pRight->token.z[0] ){
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sqliteSetNString(&pTab->aCol[i].zName,
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p->pRight->token.z, p->pRight->token.n, 0);
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}else{
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char zBuf[30];
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sprintf(zBuf, "column%d", i+1);
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pTab->aCol[i].zName = sqliteStrDup(zBuf);
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}
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}
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pTab->iPKey = -1;
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return pTab;
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}
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/*
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** For the given SELECT statement, do two things.
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**
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** (1) Fill in the pTabList->a[].pTab fields in the IdList that
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** defines the set of tables that should be scanned.
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**
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** (2) If the columns to be extracted variable (pEList) is NULL
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** (meaning that a "*" was used in the SQL statement) then
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** create a fake pEList containing the names of all columns
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** of all tables.
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**
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** Return 0 on success. If there are problems, leave an error message
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** in pParse and return non-zero.
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*/
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static int fillInColumnList(Parse *pParse, Select *p){
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int i, j, k;
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IdList *pTabList;
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ExprList *pEList;
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Table *pTab;
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if( p==0 || p->pSrc==0 ) return 1;
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pTabList = p->pSrc;
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pEList = p->pEList;
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/* Look up every table in the table list.
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*/
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for(i=0; i<pTabList->nId; i++){
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if( pTabList->a[i].pTab ){
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/* This routine has run before! No need to continue */
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return 0;
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}
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if( pTabList->a[i].zName==0 ){
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/* A sub-query in the FROM clause of a SELECT */
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assert( pTabList->a[i].pSelect!=0 );
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pTabList->a[i].pTab = pTab =
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sqliteResultSetOfSelect(pParse, pTabList->a[i].zAlias,
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pTabList->a[i].pSelect);
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if( pTab==0 ){
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return 1;
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}
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pTab->isTransient = 1;
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}else{
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/* An ordinary table or view name in the FROM clause */
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pTabList->a[i].pTab = pTab =
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sqliteFindTable(pParse->db, pTabList->a[i].zName);
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if( pTab==0 ){
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sqliteSetString(&pParse->zErrMsg, "no such table: ",
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pTabList->a[i].zName, 0);
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pParse->nErr++;
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return 1;
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}
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if( pTab->pSelect ){
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pTabList->a[i].pSelect = sqliteSelectDup(pTab->pSelect);
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}
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}
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}
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/* For every "*" that occurs in the column list, insert the names of
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** all columns in all tables. The parser inserted a special expression
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** with the TK_ALL operator for each "*" that it found in the column list.
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** The following code just has to locate the TK_ALL expressions and expand
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** each one to the list of all columns in all tables.
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*/
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for(k=0; k<pEList->nExpr; k++){
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if( pEList->a[k].pExpr->op==TK_ALL ) break;
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}
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if( k<pEList->nExpr ){
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struct ExprList_item *a = pEList->a;
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ExprList *pNew = 0;
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for(k=0; k<pEList->nExpr; k++){
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if( a[k].pExpr->op!=TK_ALL ){
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pNew = sqliteExprListAppend(pNew, a[k].pExpr, 0);
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pNew->a[pNew->nExpr-1].zName = a[k].zName;
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a[k].pExpr = 0;
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a[k].zName = 0;
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}else{
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for(i=0; i<pTabList->nId; i++){
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Table *pTab = pTabList->a[i].pTab;
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for(j=0; j<pTab->nCol; j++){
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Expr *pExpr, *pLeft, *pRight;
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pRight = sqliteExpr(TK_ID, 0, 0, 0);
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if( pRight==0 ) break;
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pRight->token.z = pTab->aCol[j].zName;
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pRight->token.n = strlen(pTab->aCol[j].zName);
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if( pTab->zName ){
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pLeft = sqliteExpr(TK_ID, 0, 0, 0);
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if( pLeft==0 ) break;
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if( pTabList->a[i].zAlias && pTabList->a[i].zAlias[0] ){
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pLeft->token.z = pTabList->a[i].zAlias;
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pLeft->token.n = strlen(pTabList->a[i].zAlias);
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}else{
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pLeft->token.z = pTab->zName;
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pLeft->token.n = strlen(pTab->zName);
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}
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pExpr = sqliteExpr(TK_DOT, pLeft, pRight, 0);
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if( pExpr==0 ) break;
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}else{
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pExpr = pRight;
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pExpr->span = pExpr->token;
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}
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pNew = sqliteExprListAppend(pNew, pExpr, 0);
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}
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}
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}
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}
|
|
sqliteExprListDelete(pEList);
|
|
p->pEList = pNew;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** This routine recursively unlinks the Select.pSrc.a[].pTab pointers
|
|
** in a select structure. It just sets the pointers to NULL. This
|
|
** routine is recursive in the sense that if the Select.pSrc.a[].pSelect
|
|
** pointer is not NULL, this routine is called recursively on that pointer.
|
|
**
|
|
** This routine is called on the Select structure that defines a
|
|
** VIEW in order to undo any bindings to tables. This is necessary
|
|
** because those tables might be DROPed by a subsequent SQL command.
|
|
*/
|
|
void sqliteSelectUnbind(Select *p){
|
|
int i;
|
|
IdList *pSrc = p->pSrc;
|
|
Table *pTab;
|
|
if( p==0 ) return;
|
|
for(i=0; i<pSrc->nId; i++){
|
|
if( (pTab = pSrc->a[i].pTab)!=0 ){
|
|
if( pTab->isTransient ){
|
|
sqliteDeleteTable(0, pTab);
|
|
sqliteSelectDelete(pSrc->a[i].pSelect);
|
|
pSrc->a[i].pSelect = 0;
|
|
}
|
|
pSrc->a[i].pTab = 0;
|
|
if( pSrc->a[i].pSelect ){
|
|
sqliteSelectUnbind(pSrc->a[i].pSelect);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This routine associates entries in an ORDER BY expression list with
|
|
** columns in a result. For each ORDER BY expression, the opcode of
|
|
** the top-level node is changed to TK_COLUMN and the iColumn value of
|
|
** the top-level node is filled in with column number and the iTable
|
|
** value of the top-level node is filled with iTable parameter.
|
|
**
|
|
** If there are prior SELECT clauses, they are processed first. A match
|
|
** in an earlier SELECT takes precedence over a later SELECT.
|
|
**
|
|
** Any entry that does not match is flagged as an error. The number
|
|
** of errors is returned.
|
|
*/
|
|
static int matchOrderbyToColumn(
|
|
Parse *pParse, /* A place to leave error messages */
|
|
Select *pSelect, /* Match to result columns of this SELECT */
|
|
ExprList *pOrderBy, /* The ORDER BY values to match against columns */
|
|
int iTable, /* Insert this this value in iTable */
|
|
int mustComplete /* If TRUE all ORDER BYs must match */
|
|
){
|
|
int nErr = 0;
|
|
int i, j;
|
|
ExprList *pEList;
|
|
|
|
if( pSelect==0 || pOrderBy==0 ) return 1;
|
|
if( mustComplete ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
|
|
}
|
|
if( fillInColumnList(pParse, pSelect) ){
|
|
return 1;
|
|
}
|
|
if( pSelect->pPrior ){
|
|
if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
|
|
return 1;
|
|
}
|
|
}
|
|
pEList = pSelect->pEList;
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
int match = 0;
|
|
if( pOrderBy->a[i].done ) continue;
|
|
for(j=0; j<pEList->nExpr; j++){
|
|
if( pEList->a[j].zName && (pE->op==TK_ID || pE->op==TK_STRING) ){
|
|
char *zName, *zLabel;
|
|
zName = pEList->a[j].zName;
|
|
assert( pE->token.z );
|
|
zLabel = sqliteStrNDup(pE->token.z, pE->token.n);
|
|
sqliteDequote(zLabel);
|
|
if( sqliteStrICmp(zName, zLabel)==0 ){
|
|
match = 1;
|
|
}
|
|
sqliteFree(zLabel);
|
|
}
|
|
if( match==0 && sqliteExprCompare(pE, pEList->a[j].pExpr) ){
|
|
match = 1;
|
|
}
|
|
if( match ){
|
|
pE->op = TK_COLUMN;
|
|
pE->iColumn = j;
|
|
pE->iTable = iTable;
|
|
pOrderBy->a[i].done = 1;
|
|
break;
|
|
}
|
|
}
|
|
if( !match && mustComplete ){
|
|
char zBuf[30];
|
|
sprintf(zBuf,"%d",i+1);
|
|
sqliteSetString(&pParse->zErrMsg, "ORDER BY term number ", zBuf,
|
|
" does not match any result column", 0);
|
|
pParse->nErr++;
|
|
nErr++;
|
|
break;
|
|
}
|
|
}
|
|
return nErr;
|
|
}
|
|
|
|
/*
|
|
** 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 *sqliteGetVdbe(Parse *pParse){
|
|
Vdbe *v = pParse->pVdbe;
|
|
if( v==0 ){
|
|
v = pParse->pVdbe = sqliteVdbeCreate(pParse->db);
|
|
}
|
|
return v;
|
|
}
|
|
|
|
|
|
/*
|
|
** This routine is called to process a query that is really the union
|
|
** or intersection of two or more separate queries.
|
|
*/
|
|
static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){
|
|
int rc; /* Success code from a subroutine */
|
|
Select *pPrior; /* Another SELECT immediately to our left */
|
|
Vdbe *v; /* Generate code to this VDBE */
|
|
int base; /* Baseline value for pParse->nTab */
|
|
|
|
/* Make sure there is no ORDER BY clause on prior SELECTs. Only the
|
|
** last SELECT in the series may have an ORDER BY.
|
|
*/
|
|
if( p==0 || p->pPrior==0 ) return 1;
|
|
pPrior = p->pPrior;
|
|
if( pPrior->pOrderBy ){
|
|
sqliteSetString(&pParse->zErrMsg,"ORDER BY clause should come after ",
|
|
selectOpName(p->op), " not before", 0);
|
|
pParse->nErr++;
|
|
return 1;
|
|
}
|
|
|
|
/* Make sure we have a valid query engine. If not, create a new one.
|
|
*/
|
|
v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) return 1;
|
|
|
|
/* Process the UNION or INTERSECTION
|
|
*/
|
|
base = pParse->nTab;
|
|
switch( p->op ){
|
|
case TK_ALL:
|
|
case TK_EXCEPT:
|
|
case TK_UNION: {
|
|
int unionTab; /* Cursor number of the temporary table holding result */
|
|
int op; /* One of the SRT_ operations to apply to self */
|
|
int priorOp; /* The SRT_ operation to apply to prior selects */
|
|
|
|
priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
|
|
if( eDest==priorOp ){
|
|
/* We can reuse a temporary table generated by a SELECT to our
|
|
** right. This also means we are not the right-most select and so
|
|
** we cannot have an ORDER BY clause
|
|
*/
|
|
unionTab = iParm;
|
|
assert( p->pOrderBy==0 );
|
|
}else{
|
|
/* We will need to create our own temporary table to hold the
|
|
** intermediate results.
|
|
*/
|
|
unionTab = pParse->nTab++;
|
|
if( p->pOrderBy
|
|
&& matchOrderbyToColumn(pParse, p, p->pOrderBy, unionTab, 1) ){
|
|
return 1;
|
|
}
|
|
if( p->op!=TK_ALL ){
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, unionTab, 1);
|
|
sqliteVdbeAddOp(v, OP_KeyAsData, unionTab, 1);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, unionTab, 0);
|
|
}
|
|
}
|
|
|
|
/* Code the SELECT statements to our left
|
|
*/
|
|
rc = sqliteSelect(pParse, pPrior, priorOp, unionTab);
|
|
if( rc ) return rc;
|
|
|
|
/* 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;
|
|
rc = sqliteSelect(pParse, p, op, unionTab);
|
|
p->pPrior = pPrior;
|
|
if( rc ) return rc;
|
|
|
|
/* Convert the data in the temporary table into whatever form
|
|
** it is that we currently need.
|
|
*/
|
|
if( eDest!=priorOp ){
|
|
int iCont, iBreak, iStart;
|
|
assert( p->pEList );
|
|
generateColumnNames(pParse, 0, p->pEList);
|
|
iBreak = sqliteVdbeMakeLabel(v);
|
|
iCont = sqliteVdbeMakeLabel(v);
|
|
sqliteVdbeAddOp(v, OP_Rewind, unionTab, iBreak);
|
|
iStart = sqliteVdbeCurrentAddr(v);
|
|
rc = selectInnerLoop(pParse, 0, unionTab, p->pEList->nExpr,
|
|
p->pOrderBy, -1, eDest, iParm,
|
|
iCont, iBreak);
|
|
if( rc ) return 1;
|
|
sqliteVdbeResolveLabel(v, iCont);
|
|
sqliteVdbeAddOp(v, OP_Next, unionTab, iStart);
|
|
sqliteVdbeResolveLabel(v, iBreak);
|
|
sqliteVdbeAddOp(v, OP_Close, unionTab, 0);
|
|
if( p->pOrderBy ){
|
|
generateSortTail(v, p->pEList->nExpr);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
case TK_INTERSECT: {
|
|
int tab1, tab2;
|
|
int iCont, iBreak, iStart;
|
|
|
|
/* 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( p->pOrderBy && matchOrderbyToColumn(pParse,p,p->pOrderBy,tab1,1) ){
|
|
return 1;
|
|
}
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, tab1, 1);
|
|
sqliteVdbeAddOp(v, OP_KeyAsData, tab1, 1);
|
|
|
|
/* Code the SELECTs to our left into temporary table "tab1".
|
|
*/
|
|
rc = sqliteSelect(pParse, pPrior, SRT_Union, tab1);
|
|
if( rc ) return rc;
|
|
|
|
/* Code the current SELECT into temporary table "tab2"
|
|
*/
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, tab2, 1);
|
|
sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1);
|
|
p->pPrior = 0;
|
|
rc = sqliteSelect(pParse, p, SRT_Union, tab2);
|
|
p->pPrior = pPrior;
|
|
if( rc ) return rc;
|
|
|
|
/* Generate code to take the intersection of the two temporary
|
|
** tables.
|
|
*/
|
|
assert( p->pEList );
|
|
generateColumnNames(pParse, 0, p->pEList);
|
|
iBreak = sqliteVdbeMakeLabel(v);
|
|
iCont = sqliteVdbeMakeLabel(v);
|
|
sqliteVdbeAddOp(v, OP_Rewind, tab1, iBreak);
|
|
iStart = sqliteVdbeAddOp(v, OP_FullKey, tab1, 0);
|
|
sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont);
|
|
rc = selectInnerLoop(pParse, 0, tab1, p->pEList->nExpr,
|
|
p->pOrderBy, -1, eDest, iParm,
|
|
iCont, iBreak);
|
|
if( rc ) return 1;
|
|
sqliteVdbeResolveLabel(v, iCont);
|
|
sqliteVdbeAddOp(v, OP_Next, tab1, iStart);
|
|
sqliteVdbeResolveLabel(v, iBreak);
|
|
sqliteVdbeAddOp(v, OP_Close, tab2, 0);
|
|
sqliteVdbeAddOp(v, OP_Close, tab1, 0);
|
|
if( p->pOrderBy ){
|
|
generateSortTail(v, p->pEList->nExpr);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
assert( p->pEList && pPrior->pEList );
|
|
if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
|
|
sqliteSetString(&pParse->zErrMsg, "SELECTs to the left and right of ",
|
|
selectOpName(p->op), " do not have the same number of result columns", 0);
|
|
pParse->nErr++;
|
|
return 1;
|
|
}
|
|
pParse->nTab = base;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** 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 using indices.
|
|
**
|
|
** This routine attempts to write 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.
|
|
**
|
|
** Generally speaking, flattening is only possible if the subquery
|
|
** query is a simple query without a GROUP BY clause or the DISTINCT
|
|
** keyword and the outer query is not a join.
|
|
**
|
|
** If flattening is not possible, this routine is a no-op and return 0.
|
|
** If flattening is possible, this routine rewrites the query into
|
|
** the simplified form and return 1.
|
|
**
|
|
** All of the expression analysis must occur before this routine runs.
|
|
** This routine depends on the results of the expression analysis.
|
|
*/
|
|
int flattenSubqueries(Select *p){
|
|
Select *pSub;
|
|
if( p->pSrc->nId>1 ){
|
|
return 0; /* Cannot optimize: The outer query is a join. */
|
|
}
|
|
pSub = p->pSrc->a[0].pSelect;
|
|
if( pSub==0 ){
|
|
return 0; /* Nothing to optimize: There is no subquery. */
|
|
}
|
|
if( pSub->isDistinct ){
|
|
return 0; /* Subquery contains DISTINCT keyword */
|
|
}
|
|
if( pSub->pGroupBy ){
|
|
return 0; /* Subquery contains a GROUP BY clause */
|
|
}
|
|
if( pSub->pPrior ){
|
|
return 0; /* Subquery is the union of two or more queries */
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** 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 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 sqliteSelect().
|
|
** 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 openOp;
|
|
int seekOp;
|
|
int cont;
|
|
ExprList eList;
|
|
struct ExprList_item eListItem;
|
|
|
|
/* 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;
|
|
if( p->pSrc->nId!=1 ) return 0;
|
|
if( p->pEList->nExpr!=1 ) return 0;
|
|
pExpr = p->pEList->a[0].pExpr;
|
|
if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
|
|
if( pExpr->pList==0 || pExpr->pList->nExpr!=1 ) return 0;
|
|
if( pExpr->token.n!=3 ) return 0;
|
|
if( sqliteStrNICmp(pExpr->token.z,"min",3)==0 ){
|
|
seekOp = OP_Rewind;
|
|
}else if( sqliteStrNICmp(pExpr->token.z,"max",3)==0 ){
|
|
seekOp = OP_Last;
|
|
}else{
|
|
return 0;
|
|
}
|
|
pExpr = pExpr->pList->a[0].pExpr;
|
|
if( pExpr->op!=TK_COLUMN ) return 0;
|
|
iCol = pExpr->iColumn;
|
|
pTab = p->pSrc->a[0].pTab;
|
|
|
|
/* 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{
|
|
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
|
assert( pIdx->nColumn>=1 );
|
|
if( pIdx->aiColumn[0]==iCol ) break;
|
|
}
|
|
if( pIdx==0 ) return 0;
|
|
}
|
|
|
|
/* Identify column names if we will be using the callback. This
|
|
** step is skipped if the output is going to a table or a memory cell.
|
|
*/
|
|
v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) return 0;
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnNames(pParse, p->pSrc, p->pEList);
|
|
}
|
|
|
|
/* 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.
|
|
*/
|
|
if( !pParse->schemaVerified && (pParse->db->flags & SQLITE_InTrans)==0 ){
|
|
sqliteVdbeAddOp(v, OP_VerifyCookie, pParse->db->schema_cookie, 0);
|
|
pParse->schemaVerified = 1;
|
|
}
|
|
openOp = pTab->isTemp ? OP_OpenAux : OP_Open;
|
|
base = pParse->nTab;
|
|
sqliteVdbeAddOp(v, openOp, base, pTab->tnum);
|
|
sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
|
|
if( pIdx==0 ){
|
|
sqliteVdbeAddOp(v, seekOp, base, 0);
|
|
}else{
|
|
sqliteVdbeAddOp(v, openOp, base+1, pIdx->tnum);
|
|
sqliteVdbeChangeP3(v, -1, pIdx->zName, P3_STATIC);
|
|
sqliteVdbeAddOp(v, seekOp, base+1, 0);
|
|
sqliteVdbeAddOp(v, OP_IdxRecno, base+1, 0);
|
|
sqliteVdbeAddOp(v, OP_Close, base+1, 0);
|
|
sqliteVdbeAddOp(v, OP_MoveTo, base, 0);
|
|
}
|
|
eList.nExpr = 1;
|
|
memset(&eListItem, 0, sizeof(eListItem));
|
|
eList.a = &eListItem;
|
|
eList.a[0].pExpr = pExpr;
|
|
cont = sqliteVdbeMakeLabel(v);
|
|
selectInnerLoop(pParse, &eList, base, 1, 0, -1, eDest, iParm, cont, cont);
|
|
sqliteVdbeResolveLabel(v, cont);
|
|
sqliteVdbeAddOp(v, OP_Close, base, 0);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
** 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 a table with cursor iParm
|
|
**
|
|
** SRT_Union Store results as a key in a temporary table iParm
|
|
**
|
|
** SRT_Except Remove results form the temporary table iParm.
|
|
**
|
|
** SRT_Table Store results in temporary table iParm
|
|
**
|
|
** 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.
|
|
*/
|
|
int sqliteSelect(
|
|
Parse *pParse, /* The parser context */
|
|
Select *p, /* The SELECT statement being coded. */
|
|
int eDest, /* One of: SRT_Callback Mem Set Union Except */
|
|
int iParm /* Save result in this memory location, if >=0 */
|
|
){
|
|
int i;
|
|
WhereInfo *pWInfo;
|
|
Vdbe *v;
|
|
int isAgg = 0; /* True for select lists like "count(*)" */
|
|
ExprList *pEList; /* List of columns to extract. */
|
|
IdList *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 base; /* First cursor available for use */
|
|
int rc = 1; /* Value to return from this function */
|
|
|
|
if( sqlite_malloc_failed || pParse->nErr || p==0 ) return 1;
|
|
|
|
/* If there is are a sequence of queries, do the earlier ones first.
|
|
*/
|
|
if( p->pPrior ){
|
|
return multiSelect(pParse, p, eDest, iParm);
|
|
}
|
|
|
|
/* Make local copies of the parameters for this query.
|
|
*/
|
|
pTabList = p->pSrc;
|
|
pWhere = p->pWhere;
|
|
pOrderBy = p->pOrderBy;
|
|
pGroupBy = p->pGroupBy;
|
|
pHaving = p->pHaving;
|
|
isDistinct = p->isDistinct;
|
|
|
|
/* Save the current value of pParse->nTab. Restore this value before
|
|
** we exit.
|
|
*/
|
|
base = pParse->nTab;
|
|
|
|
/*
|
|
** 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;
|
|
|
|
/* Look up every table in the table list and create an appropriate
|
|
** columnlist in pEList if there isn't one already. (The parser leaves
|
|
** a NULL in the p->pEList if the SQL said "SELECT * FROM ...")
|
|
*/
|
|
if( fillInColumnList(pParse, p) ){
|
|
goto select_end;
|
|
}
|
|
pEList = p->pEList;
|
|
if( pEList==0 ) goto select_end;
|
|
|
|
/* Allocate a temporary table to use for the DISTINCT set, if
|
|
** necessary. This must be done early to allocate the cursor before
|
|
** any calls to sqliteExprResolveIds().
|
|
*/
|
|
if( isDistinct ){
|
|
distinct = pParse->nTab++;
|
|
}else{
|
|
distinct = -1;
|
|
}
|
|
|
|
/* If writing to memory or generating a set
|
|
** only a single column may be output.
|
|
*/
|
|
if( (eDest==SRT_Mem || eDest==SRT_Set) && pEList->nExpr>1 ){
|
|
sqliteSetString(&pParse->zErrMsg, "only a single result allowed for "
|
|
"a SELECT that is part of an expression", 0);
|
|
pParse->nErr++;
|
|
goto select_end;
|
|
}
|
|
|
|
/* ORDER BY is ignored if we are not sending the result to a callback.
|
|
*/
|
|
if( eDest!=SRT_Callback ){
|
|
pOrderBy = 0;
|
|
}
|
|
|
|
/* Allocate cursors for "expr IN (SELECT ...)" constructs.
|
|
*/
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
sqliteExprResolveInSelect(pParse, pEList->a[i].pExpr);
|
|
}
|
|
if( pWhere ) sqliteExprResolveInSelect(pParse, pWhere);
|
|
if( pOrderBy ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
sqliteExprResolveInSelect(pParse, pOrderBy->a[i].pExpr);
|
|
}
|
|
}
|
|
if( pGroupBy ){
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
sqliteExprResolveInSelect(pParse, pGroupBy->a[i].pExpr);
|
|
}
|
|
}
|
|
if( pHaving ) sqliteExprResolveInSelect(pParse, pHaving);
|
|
|
|
/* At this point, we should have allocated all the cursors that we
|
|
** need to handle subquerys and temporary tables. From here on we
|
|
** are committed to keeping the same value for pParse->nTab.
|
|
**
|
|
** Resolve the column names and do a semantics check on all the expressions.
|
|
*/
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
if( sqliteExprResolveIds(pParse, pTabList, 0, pEList->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &isAgg) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pWhere ){
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pWhere) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pOrderBy ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
if( sqliteExprIsConstant(pE) ){
|
|
sqliteSetString(&pParse->zErrMsg,
|
|
"ORDER BY expressions should not be constant", 0);
|
|
pParse->nErr++;
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pE) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
if( pGroupBy ){
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
Expr *pE = pGroupBy->a[i].pExpr;
|
|
if( sqliteExprIsConstant(pE) ){
|
|
sqliteSetString(&pParse->zErrMsg,
|
|
"GROUP BY expressions should not be constant", 0);
|
|
pParse->nErr++;
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pE) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
if( pHaving ){
|
|
if( pGroupBy==0 ){
|
|
sqliteSetString(&pParse->zErrMsg, "a GROUP BY clause is required "
|
|
"before HAVING", 0);
|
|
pParse->nErr++;
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pHaving) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pHaving, isAgg, 0) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
|
|
/* Try to merge subqueries in the FROM clause into the main
|
|
** query.
|
|
*/
|
|
if( flattenSubqueries(p) ){
|
|
pEList = p->pEList;
|
|
pWhere = p->pWhere;
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
|
|
/* Begin generating code.
|
|
*/
|
|
v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) goto select_end;
|
|
|
|
/* Generate code for all sub-queries in the FROM clause
|
|
*/
|
|
for(i=0; i<pTabList->nId; i++){
|
|
int oldNTab;
|
|
if( pTabList->a[i].pSelect==0 ) continue;
|
|
oldNTab = pParse->nTab;
|
|
pParse->nTab += i+1;
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, oldNTab+i, 0);
|
|
sqliteSelect(pParse, pTabList->a[i].pSelect, SRT_Table, oldNTab+i);
|
|
pParse->nTab = oldNTab;
|
|
}
|
|
|
|
/* Do an analysis of aggregate expressions.
|
|
*/
|
|
sqliteAggregateInfoReset(pParse);
|
|
if( isAgg ){
|
|
assert( pParse->nAgg==0 );
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
if( sqliteExprAnalyzeAggregates(pParse, pEList->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pGroupBy ){
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
if( sqliteExprAnalyzeAggregates(pParse, pGroupBy->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
if( pHaving && sqliteExprAnalyzeAggregates(pParse, pHaving) ){
|
|
goto select_end;
|
|
}
|
|
if( pOrderBy ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
if( sqliteExprAnalyzeAggregates(pParse, pOrderBy->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Set the limiter
|
|
*/
|
|
if( p->nLimit<=0 ){
|
|
p->nOffset = 0;
|
|
}else{
|
|
if( p->nOffset<0 ) p->nOffset = 0;
|
|
sqliteVdbeAddOp(v, OP_Limit, p->nLimit, p->nOffset);
|
|
}
|
|
|
|
|
|
/* Identify column names if we will be using in the callback. This
|
|
** step is skipped if the output is going to a table or a memory cell.
|
|
*/
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnNames(pParse, pTabList, pEList);
|
|
}
|
|
|
|
/* Reset the aggregator
|
|
*/
|
|
if( isAgg ){
|
|
sqliteVdbeAddOp(v, OP_AggReset, 0, pParse->nAgg);
|
|
for(i=0; i<pParse->nAgg; i++){
|
|
FuncDef *pFunc;
|
|
if( (pFunc = pParse->aAgg[i].pFunc)!=0 && pFunc->xFinalize!=0 ){
|
|
sqliteVdbeAddOp(v, OP_AggInit, 0, i);
|
|
sqliteVdbeChangeP3(v, -1, (char*)pFunc, P3_POINTER);
|
|
}
|
|
}
|
|
if( pGroupBy==0 ){
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_AggFocus, 0, 0);
|
|
}
|
|
}
|
|
|
|
/* Initialize the memory cell to NULL
|
|
*/
|
|
if( eDest==SRT_Mem ){
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
|
|
}
|
|
|
|
/* Begin the database scan
|
|
*/
|
|
if( isDistinct ){
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, distinct, 1);
|
|
}
|
|
pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0);
|
|
if( pWInfo==0 ) goto select_end;
|
|
|
|
/* Use the standard inner loop if we are not dealing with
|
|
** aggregates
|
|
*/
|
|
if( !isAgg ){
|
|
if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
|
|
pWInfo->iContinue, pWInfo->iBreak) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
|
|
/* If we are dealing with aggregates, then to the special aggregate
|
|
** processing.
|
|
*/
|
|
else{
|
|
if( pGroupBy ){
|
|
int lbl1;
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
sqliteExprCode(pParse, pGroupBy->a[i].pExpr);
|
|
}
|
|
sqliteVdbeAddOp(v, OP_MakeKey, pGroupBy->nExpr, 0);
|
|
lbl1 = sqliteVdbeMakeLabel(v);
|
|
sqliteVdbeAddOp(v, OP_AggFocus, 0, lbl1);
|
|
for(i=0; i<pParse->nAgg; i++){
|
|
if( pParse->aAgg[i].isAgg ) continue;
|
|
sqliteExprCode(pParse, pParse->aAgg[i].pExpr);
|
|
sqliteVdbeAddOp(v, OP_AggSet, 0, i);
|
|
}
|
|
sqliteVdbeResolveLabel(v, lbl1);
|
|
}
|
|
for(i=0; i<pParse->nAgg; i++){
|
|
Expr *pE;
|
|
int j;
|
|
if( !pParse->aAgg[i].isAgg ) continue;
|
|
pE = pParse->aAgg[i].pExpr;
|
|
assert( pE->op==TK_AGG_FUNCTION );
|
|
if( pE->pList ){
|
|
for(j=0; j<pE->pList->nExpr; j++){
|
|
sqliteExprCode(pParse, pE->pList->a[j].pExpr);
|
|
}
|
|
}
|
|
sqliteVdbeAddOp(v, OP_Integer, i, 0);
|
|
sqliteVdbeAddOp(v, OP_AggFunc, 0, pE->pList ? pE->pList->nExpr : 0);
|
|
assert( pParse->aAgg[i].pFunc!=0 );
|
|
assert( pParse->aAgg[i].pFunc->xStep!=0 );
|
|
sqliteVdbeChangeP3(v, -1, (char*)pParse->aAgg[i].pFunc, P3_POINTER);
|
|
}
|
|
}
|
|
|
|
/* End the database scan loop.
|
|
*/
|
|
sqliteWhereEnd(pWInfo);
|
|
|
|
/* If we are processing aggregates, we need to set up a second loop
|
|
** over all of the aggregate values and process them.
|
|
*/
|
|
if( isAgg ){
|
|
int endagg = sqliteVdbeMakeLabel(v);
|
|
int startagg;
|
|
startagg = sqliteVdbeAddOp(v, OP_AggNext, 0, endagg);
|
|
pParse->useAgg = 1;
|
|
if( pHaving ){
|
|
sqliteExprIfFalse(pParse, pHaving, startagg);
|
|
}
|
|
if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
|
|
startagg, endagg) ){
|
|
goto select_end;
|
|
}
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, startagg);
|
|
sqliteVdbeResolveLabel(v, endagg);
|
|
sqliteVdbeAddOp(v, OP_Noop, 0, 0);
|
|
pParse->useAgg = 0;
|
|
}
|
|
|
|
/* 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(v, pEList->nExpr);
|
|
}
|
|
pParse->nTab = base;
|
|
|
|
|
|
/* Issue a null callback if that is what the user wants.
|
|
*/
|
|
if( (pParse->db->flags & SQLITE_NullCallback)!=0 && eDest==SRT_Callback ){
|
|
sqliteVdbeAddOp(v, OP_NullCallback, pEList->nExpr, 0);
|
|
}
|
|
|
|
/* 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:
|
|
sqliteAggregateInfoReset(pParse);
|
|
return rc;
|
|
}
|