From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrey Rachitskiy <pl0h0yp1@gmail.com>
cc: malis@pgrust.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19619: WHERE scale(n) = 1 pushed past GROUP BY / window
 PARTITION BY, wrong COUNT
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References: <19619-fc646db1c6b2dc90@postgresql.org>
 <CAB8bMiu2POh0dcsjUaqCwaABZcdNkm73ymcU10F3=2Qz8rKsgw@mail.gmail.com>
Comments: In-reply-to Andrey Rachitskiy <pl0h0yp1@gmail.com>
	message dated "Fri, 14 Aug 2026 23:30:17 +0500"
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Date: Fri, 14 Aug 2026 14:51:03 -0400
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Andrey Rachitskiy <pl0h0yp1@gmail.com> writes:
> Tom's view on the HAVING form was that the query is ill-posed.
> The group's representative among equal numerics is unspecified, so
> HAVING scale(c) = 1 after grouping is not well defined.
> https://postgr.es/m/1738062.1784927903@sss.pgh.pa.us

Yeah.  I'd be more excited about doing something about this if we'd
required opclasses to say whether their equality operator is image
equality or something weaker.  But that was never designed into the
system, and retrofitting it now would be a mess.  Since the only
benefit would be to queries that are arguably wrong anyway, it's
difficult to justify the effort.

			regards, tom lane