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Test HAVING condition before computing targetlist of an Aggregate node.

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This is required by SQL spec to avoid failures in cases like
  SELECT sum(win)/sum(lose) FROM ... GROUP BY ... HAVING sum(lose) > 0;
AFAICT we have gotten this wrong since day one.  Kudos to Holger Jakobs
for being the first to notice.
This commit is contained in:
Tom Lane 2004-07-10 18:39:23 +00:00
parent afa035c204
commit 82f755ec80
1 changed files with 34 additions and 30 deletions

64
src/backend/executor/nodeAgg.c

@ -45,7 +45,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.122 2004/06/06 00:41:26 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.123 2004/07/10 18:39:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -674,7 +674,6 @@ agg_retrieve_direct(AggState *aggstate)
AggStatePerGroup pergroup;
TupleTableSlot *outerslot;
TupleTableSlot *firstSlot;
TupleTableSlot *resultSlot;
int aggno;
/*
@ -696,11 +695,8 @@ agg_retrieve_direct(AggState *aggstate)
* We loop retrieving groups until we find one matching
* aggstate->ss.ps.qual
*/
do
while (!aggstate->agg_done)
{
if (aggstate->agg_done)
return NULL;
/*
* If we don't already have the first tuple of the new group,
* fetch it from the outer plan.
@ -815,7 +811,7 @@ agg_retrieve_direct(AggState *aggstate)
/*
* If we have no first tuple (ie, the outerPlan didn't return
* anything), create a dummy all-nulls input tuple for use by
* ExecProject. 99.44% of the time this is a waste of cycles,
* ExecQual/ExecProject. 99.44% of the time this is a waste of cycles,
* because ordinarily the projected output tuple's targetlist
* cannot contain any direct (non-aggregated) references to input
* columns, so the dummy tuple will not be referenced. However
@ -857,22 +853,28 @@ agg_retrieve_direct(AggState *aggstate)
}
/*
* Form a projection tuple using the aggregate results and the
* representative input tuple. Store it in the result tuple slot.
* Note we do not support aggregates returning sets ...
* Use the representative input tuple for any references to
* non-aggregated input columns in the qual and tlist.
*/
econtext->ecxt_scantuple = firstSlot;
resultSlot = ExecProject(projInfo, NULL);
/*
* If the completed tuple does not match the qualifications, it is
* ignored and we loop back to try to process another group.
* Otherwise, return the tuple.
* Check the qual (HAVING clause); if the group does not match,
* ignore it and loop back to try to process another group.
*/
if (ExecQual(aggstate->ss.ps.qual, econtext, false))
{
/*
* Form and return a projection tuple using the aggregate results
* and the representative input tuple. Note we do not support
* aggregates returning sets ...
*/
return ExecProject(projInfo, NULL);
}
}
while (!ExecQual(aggstate->ss.ps.qual, econtext, false));
return resultSlot;
/* No more groups */
return NULL;
}
/*
@ -934,7 +936,6 @@ agg_retrieve_hash_table(AggState *aggstate)
AggStatePerGroup pergroup;
AggHashEntry entry;
TupleTableSlot *firstSlot;
TupleTableSlot *resultSlot;
int aggno;
/*
@ -952,11 +953,8 @@ agg_retrieve_hash_table(AggState *aggstate)
* We loop retrieving groups until we find one satisfying
* aggstate->ss.ps.qual
*/
do
while (!aggstate->agg_done)
{
if (aggstate->agg_done)
return NULL;
/*
* Find the next entry in the hash table
*/
@ -999,22 +997,28 @@ agg_retrieve_hash_table(AggState *aggstate)
}
/*
* Form a projection tuple using the aggregate results and the
* representative input tuple. Store it in the result tuple slot.
* Note we do not support aggregates returning sets ...
* Use the representative input tuple for any references to
* non-aggregated input columns in the qual and tlist.
*/
econtext->ecxt_scantuple = firstSlot;
resultSlot = ExecProject(projInfo, NULL);
/*
* If the completed tuple does not match the qualifications, it is
* ignored and we loop back to try to process another group.
* Otherwise, return the tuple.
* Check the qual (HAVING clause); if the group does not match,
* ignore it and loop back to try to process another group.
*/
if (ExecQual(aggstate->ss.ps.qual, econtext, false))
{
/*
* Form and return a projection tuple using the aggregate results
* and the representative input tuple. Note we do not support
* aggregates returning sets ...
*/
return ExecProject(projInfo, NULL);
}
}
while (!ExecQual(aggstate->ss.ps.qual, econtext, false));
return resultSlot;
/* No more groups */
return NULL;
}
/* -----------------