Re: [HACKERS] having bug report

Sorry. I re-sent this message because I don't see it in TODO file and I
thougth it was fixed.

Tom Lane ha scritto:

> =?iso-8859-1?Q?Jos=E9?= Soares <jose(at)sferacarta(dot)com> writes:
> > * subqueries containing HAVING return incorrect results
> > select istat from comuni where istat in (
> > select istat from comuni group by istat having count(istat) > 1
> > );
> > ERROR: rewrite: aggregate column of view must be at rigth side in qual
> > select istat from comuni where istat in (
> > select istat from comuni group by istat having 1 < count(istat)
> > );
> > ERROR: pull_var_clause: Cannot handle node type 108
>
> These are both known problems (at least, I had both in my todo list).
>
> The first one appears to be a rewriter bug --- it seems to want to
> implement count(istat) as a second nested sublink, and then it falls
> over because it doesn't handle "subselect op something" as opposed to
> "something op subselect". But pushing count(istat) into a subselect
> is not merely inefficient, it's *wrong* in this case because then the
> group by won't affect it.
>
> The second one is a problem in the planner/optimizer; it falls over on
> sublinks in HAVING clauses (of course, this particular example wouldn't
> trigger the problem were it not for the upstream rewriter bug, but it's
> still a planner bug). I think union_planner's handling of sublinks
> needs considerable work, but was putting it off till after 6.5.
>
> I will work on the second problem; I think the first one is in Jan's
> turf...
>
> regards, tom lane

Jose'