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Call the query flattener while processing the parent query. Previously, it was called while processing the sub-queries. (CVS 5330)

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FossilOrigin-Name: 6fcb3bffe26ae1c21c72ce9019f1db1c118094a4
This commit is contained in:
danielk1977
2008-06-30 18:12:28 +00:00
parent 63703a42f1
commit daf79acb68
4 changed files with 55 additions and 42 deletions
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61
src/select.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.439 2008/06/27 00:52:45 drh Exp $
** $Id: select.c,v 1.440 2008/06/30 18:12:28 danielk1977 Exp $
*/
#include "sqliteInt.h"
@@ -3670,6 +3670,7 @@ int sqlite3Select(
}
p->pOrderBy = pOrderBy;
#ifndef SQLITE_OMIT_COMPOUND_SELECT
/* If there is are a sequence of queries, do the earlier ones first.
*/
@@ -3696,11 +3697,7 @@ int sqlite3Select(
/* 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;
@@ -3734,19 +3731,21 @@ int sqlite3Select(
*/
#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
for(i=0; i<pTabList->nSrc; i++){
const char *zSavedAuthContext = 0;
int needRestoreContext;
struct SrcList_item *pItem = &pTabList->a[i];
SelectDest dest;
Select *pSub = pItem->pSelect;
if( pItem->pSelect==0 || pItem->isPopulated ) continue;
if( pItem->zName!=0 ){
zSavedAuthContext = pParse->zAuthContext;
if( pSub==0 || pItem->isPopulated ) continue;
if( pItem->zName!=0 ){ /* An sql view */
const char *zSavedAuthContext = pParse->zAuthContext;
pParse->zAuthContext = pItem->zName;
needRestoreContext = 1;
}else{
needRestoreContext = 0;
rc = sqlite3SelectResolve(pParse, pSub, 0);
pParse->zAuthContext = zSavedAuthContext;
if( rc ){
goto select_end;
}
}
/* Increment Parse.nHeight by the height of the largest expression
** tree refered to by this, the parent select. The child select
** may contain expression trees of at most
@@ -3755,36 +3754,32 @@ int sqlite3Select(
** an exact limit.
*/
pParse->nHeight += sqlite3SelectExprHeight(p);
sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
sqlite3Select(pParse, pItem->pSelect, &dest, p, i, &isAgg, 0);
/* Check to see if the subquery can be absorbed into the parent. */
if( !pSub->pPrior && flattenSubquery(db, p, i, isAgg, pSub->isAgg) ){
if( pSub->isAgg ){
p->isAgg = isAgg = 1;
}
i = -1;
}else{
sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
sqlite3Select(pParse, pSub, &dest, p, i, &isAgg, 0);
}
if( db->mallocFailed ){
goto select_end;
}
pParse->nHeight -= sqlite3SelectExprHeight(p);
if( needRestoreContext ){
pParse->zAuthContext = zSavedAuthContext;
}
pTabList = p->pSrc;
pWhere = p->pWhere;
if( !IgnorableOrderby(pDest) ){
pOrderBy = p->pOrderBy;
}
pGroupBy = p->pGroupBy;
pHaving = p->pHaving;
isDistinct = p->isDistinct;
}
#endif
/* 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;
}
pEList = p->pEList;
#endif
pWhere = p->pWhere;
pGroupBy = p->pGroupBy;
pHaving = p->pHaving;
isDistinct = p->isDistinct;
/* If possible, rewrite the query to use GROUP BY instead of DISTINCT.
** GROUP BY may use an index, DISTINCT never does.