From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>,
        Tomas Vondra <tomas.vondra@enterprisedb.com>
Subject: Re: ERROR: PlaceHolderVar found where not expected
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Comments: In-reply-to Richard Guo <guofenglinux@gmail.com>
	message dated "Tue, 14 Mar 2023 11:01:40 +0800"
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Date: Mon, 13 Mar 2023 23:32:31 -0400
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Richard Guo <guofenglinux@gmail.com> writes:
> I came across an ERROR as $subject with query below.
> ...
> This is due to that we use 0 flags for pull_var_clause in
> dependency_is_compatible_expression, assuming that the 'clause_expr'
> cannot contain Aggrefs, WindowFuncs or PlaceHolderVars.  This should be
> an oversight as we can see that it's possible to find PHVs here.

Nice catch.

> But I'm not sure if Aggrefs and WindowFuncs are possible to be found
> here.

WindowFuncs should be disallowed in qual clauses, so I think it's okay
to leave those flags out.  An Aggref could occur in a HAVING qual though.
I'm not sure if this code could get applied to HAVING ... but it's
not immediately clear that it can't.  I'd be inclined to add
PVC_RECURSE_AGGREGATES, as that seems more likely to be okay than not.

			regards, tom lane