database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-14 00:22:38 +03:00
Code Activity

Disable the query flattening optimization when the subquery is a compound

Browse Source 
query with an ORDER BY clause.  Ticket #3773 shows why that combination
does not work. (CVS 6437)

FossilOrigin-Name: 23f90d50737a36ebd17152dd4667948ce7049967
This commit is contained in:
drh
2009-04-02 16:59:47 +00:00
parent 3034e3d364
commit e8902a70fe
5 changed files with 88 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
src/select.c
View File

@@ -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 1.506 2009/03/31 03:41:57 shane Exp $
** $Id: select.c,v 1.507 2009/04/02 16:59:47 drh Exp $
*/
#include "sqliteInt.h"
@@ -2555,6 +2555,12 @@ static void substSelect(
** (19) The subquery does not use LIMIT or the outer query does not
** have a WHERE clause.
**
** (20) If the sub-query is a compound select, then it must not use
** an ORDER BY clause. Ticket #3773. We could relax this constraint
** somewhat by saying that the terms of the ORDER BY clause must
** appear as unmodified result columns in the outer query. But
** have other optimizations in mind to deal with that case.
**
** 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.
@@ -2665,6 +2671,9 @@ static int flattenSubquery(
** queries.
*/
if( pSub->pPrior ){
if( pSub->pOrderBy ){
return 0; /* Restriction 20 */
}
if( isAgg || (p->selFlags & SF_Distinct)!=0 || pSrc->nSrc!=1 ){
return 0;
}