From: hubert depesz lubaczewski <depesz@depesz.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: order by alias - doesn't work sometimes?
Date: Tue, 14 Oct 2025 17:46:23 +0200
Message-ID: <aO5wT-h2C5WACgaq@depesz.com> (raw)
In-Reply-To: <959907.1760454631@sss.pgh.pa.us>
References: <aO5jUGlQgBBAOp4_@depesz.com>
<959907.1760454631@sss.pgh.pa.us>
On Tue, Oct 14, 2025 at 11:10:31AM -0400, Tom Lane wrote:
> ORDER BY output-column-alias is a messy hangover from SQL92.
> In later SQL versions, identifiers in ORDER BY have the same
> interpretation as in WHERE and other clauses, namely they are
> columns sourced by the FROM clause. Supporting both interpretations
> makes for a lot of ambiguity, so we only allow the old interpretation
> in exactly the case required by SQL92, namely "ORDER BY identifier".
>
> This is documented ...
Well, now I understand this:
>> Each expression can be the name or ordinal number of an output column
>> (SELECT list item), or it can be an arbitrary expression formed from
>> input-column values.
better. Thanks.
Best regards,
depesz
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To: pgsql-bugs@postgresql.org
Cc: depesz@depesz.com, tgl@sss.pgh.pa.us, pgsql-bugs@lists.postgresql.org
Subject: Re: order by alias - doesn't work sometimes?
In-Reply-To: <aO5wT-h2C5WACgaq@depesz.com>
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