diff options
Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/src/select.c b/src/select.c index a6513afca..e0ac9db97 100644 --- a/src/select.c +++ b/src/select.c @@ -6386,7 +6386,8 @@ int sqlite3Select( /* If a FROM-clause subquery has an ORDER BY clause that is not ** really doing anything, then delete it now so that it does not - ** interfere with query flattening. + ** interfere with query flattening. See the discussion at + ** https://sqlite.org/forum/forumpost/2d76f2bcf65d256a ** ** Beware of these cases where the ORDER BY clause may not be safely ** omitted: @@ -6394,13 +6395,20 @@ int sqlite3Select( ** (1) There is also a LIMIT clause ** (2) The subquery was added to help with window-function ** processing - ** (3) The outer query uses an aggregate function other than + ** (3) The subquery is in the FROM clause of an UPDATE + ** (4) The outer query uses an aggregate function other than ** the built-in count(), min(), or max(). + ** (5) The ORDER BY isn't going to accomplish anything because + ** one of: + ** (a) The outer query has a different ORDER BY clause + ** (b) The subquery is part of a join + ** See forum post 062d576715d277c8 */ if( pSub->pOrderBy!=0 + && (p->pOrderBy!=0 || pTabList->nSrc>1) /* Condition (5) */ && pSub->pLimit==0 /* Condition (1) */ && (pSub->selFlags & SF_OrderByReqd)==0 /* Condition (2) */ - && (p->selFlags & SF_OrderByReqd)==0 /* Condition (3) */ + && (p->selFlags & SF_OrderByReqd)==0 /* Condition (3) and (4) */ && OptimizationEnabled(db, SQLITE_OmitOrderBy) ){ SELECTTRACE(0x100,pParse,p, |