From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: kyle@lahnakoski.com
To: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17232: DISTINCT ON does not allow AS
Date: Sat, 16 Oct 2021 11:59:15 -0300
Message-ID: <202110161459.hufnhzw4bosn@alvherre.pgsql> (raw)
In-Reply-To: <17232-f7e20e9639b6a6c9@postgresql.org>
On 2021-Oct-15, PG Bug reporting form wrote:
> The following SQL has an unexpected syntax error
>
> SELECT DISTINCT ON (col) AS col, col2 FROM test
Well, the "ON (col)" part is not an output column -- it's just the
specification of the column that you want distinctness over. I suspect
you mean
SELECT DISTINCT ON (col) col AS col, col2 FROM test
... which looks like a pretty bogus thing to do, since you have no say
on *which* values of col2 are you going to get for each distinct value
of col. But ... it gives *some* result, at least.
--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
"Pensar que el espectro que vemos es ilusorio no lo despoja de espanto,
sólo le suma el nuevo terror de la locura" (Perelandra, C.S. Lewis)
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To: pgsql-bugs@postgresql.org
Cc: alvherre@alvh.no-ip.org, kyle@lahnakoski.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17232: DISTINCT ON does not allow AS
In-Reply-To: <202110161459.hufnhzw4bosn@alvherre.pgsql>
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