From: Tod McQuillin <devin@spamcop.net>
To: Carlos <carlos@solaria-mediterranea.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Select distinct and order by.
Date: Tue, 17 Jul 2001 08:25:15 -0500 (CDT)
Message-ID: <Pine.GSO.4.33.0107170818360.13580-100000@sysadmin> (raw)
In-Reply-To: <3B4C1145.97056A0A@solaria-mediterranea.com>
On Wed, 11 Jul 2001, Carlos wrote:
> Select distinct field1, field2 from table1 order by field3;
>
> The value return by PQresultErrorMessage is:
>
> For SELECT DISTINCT, ORDER BY expressions must appear in target list
That's because this query is ambiguous.
What if table1 looks like this:
field1 field2 field3
------ ------ ------
a b 1
a b 3
c d 2
What should your query return then? Both
a b
c d
and
c d
a b
are valid, depending on which 'a b' row was chosen.
If 6.5.3 allowed that, it was a mistake to rely on it because the answer
is undefined.
--
Tod McQuillin
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To: pgsql-sql@postgresql.org
Cc: devin@spamcop.net, carlos@solaria-mediterranea.com
Subject: Re: Select distinct and order by.
In-Reply-To: <Pine.GSO.4.33.0107170818360.13580-100000@sysadmin>
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