From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <dgrowleyml@gmail.com>
cc: =?UTF-8?Q?Daniel_Farka=C5=A1?= <daniel.farkas@datoris.com>,
        Magnus Hagander <magnus@hagander.net>,
        PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #17502: View based on window functions returns wrong results
 when queried
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Comments: In-reply-to David Rowley <dgrowleyml@gmail.com>
	message dated "Mon, 30 May 2022 10:30:14 +1200"
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Date: Sun, 29 May 2022 22:18:59 -0400
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David Rowley <dgrowleyml@gmail.com> writes:
> The problem seems to be down to the fact that
> remove_unused_subquery_outputs() does not check if the to-be-removed
> target entry references WindowClauses which contain set-returning
> functions.

I was sort of wondering why we allow SRFs in this context in the
first place.  The results don't seem terribly well-defined to me.
In particular, a WindowFunc invocation is not supposed to change the
number of rows in the query result, and yet this one is doing so.

			regards, tom lane