diff options
Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/select.c b/src/select.c index 42a476c00..0925f102e 100644 --- a/src/select.c +++ b/src/select.c @@ -5009,6 +5009,13 @@ static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){ ** be materialized. (This restriction is implemented in the calling ** routine.) ** +** (8) The subquery may not be a compound that uses UNION, INTERSECT, +** or EXCEPT. (We could, perhaps, relax this restriction to allow +** this case if none of the comparisons operators between left and +** right arms of the compound use a collation other than BINARY. +** But it is a lot of work to check that case for an obscure and +** minor optimization, so we omit it for now.) +** ** Return 0 if no changes are made and non-zero if one or more WHERE clause ** terms are duplicated into the subquery. */ @@ -5028,6 +5035,10 @@ static int pushDownWhereTerms( if( pSubq->pPrior ){ Select *pSel; for(pSel=pSubq; pSel; pSel=pSel->pPrior){ + u8 op = pSel->op; + assert( op==TK_ALL || op==TK_SELECT + || op==TK_UNION || op==TK_INTERSECT || op==TK_EXCEPT ); + if( op!=TK_ALL && op!=TK_SELECT ) return 0; /* restriction (8) */ if( pSel->pWin ) return 0; /* restriction (6b) */ } }else{ |