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Replaced targetlist entry in GroupClause by reference number

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in Resdom and GroupClause so changing of resno's doesn't confuse
the grouping any more.

Jan
This commit is contained in:
Jan Wieck
1999-05-12 15:02:39 +00:00
parent 1a87c14c9c
commit 79c2576f77
22 changed files with 242 additions and 199 deletions
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45
src/backend/optimizer/prep/preptlist.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.18 1999/02/13 23:16:38 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.19 1999/05/12 15:01:41 wieck Exp $
*
*-------------------------------------------------------------------------
*/
@ -229,6 +229,49 @@ replace_matching_resname(List *new_tlist, List *old_tlist)
new_tl = makeTargetEntry(newresno, old_tle->expr);
t_list = lappend(t_list, new_tl);
}
/*
* Also it is possible that the parser or rewriter added
* some junk attributes to hold GROUP BY expressions which
* are not part of the result attributes.
* We can simply identify them by looking at the resgroupref
* in the TLE's resdom, which is a unique number telling which
* TLE belongs to which GroupClause.
*/
if (old_tle->resdom->resgroupref > 0)
{
bool already_there = FALSE;
TargetEntry *new_tle;
Resdom *newresno;
/*
* Check if the tle is already in the new list
*/
foreach(i, t_list)
{
new_tle = (TargetEntry *)lfirst(i);
if (new_tle->resdom->resgroupref ==
old_tle->resdom->resgroupref)
{
already_there = TRUE;
break;
}
}
/*
* If not, add it and make sure it is now a junk attribute
*/
if (!already_there)
{
newresno = (Resdom *) copyObject((Node *) old_tle->resdom);
newresno->resno = length(t_list) + 1;
newresno->resjunk = 1;
new_tl = makeTargetEntry(newresno, old_tle->expr);
t_list = lappend(t_list, new_tl);
}
}
}
return t_list;