From: Bruno Wolff III <bruno@wolff.to>
To: Volkan YAZICI <yazicivo@ttnet.net.tr>
Cc: Everton Luís Berz <everton.berz@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Sorting aggregate column contents
Date: Tue, 2 May 2006 19:16:02 -0500
Message-ID: <20060503001602.GC31652@wolff.to> (raw)
In-Reply-To: <20060502211340.GA188@alamut>
References: <4457C86F.8040303@gmail.com>
<20060502211340.GA188@alamut>
On Wed, May 03, 2006 at 00:13:40 +0300,
Volkan YAZICI <yazicivo@ttnet.net.tr> wrote:
> On May 02 06:00, Everton Luís Berz wrote:
> > Is it possible to sort the content of an aggregate text column?
> >
> > Query:
> > select s.name, ag_concat(c.name) from state s
> > inner join city c on (c.idstate = s.idstate)
> > group by s.name
> > order by s.name;
>
> IMHO, you can receive results ordered by using a subselect:
>
> SELECT T.s_name, ag_concat(T.c_name)
> FROM (SELECT s.name, c.name
> FROM state AS s
> INNER JOIN city AS c ON (c.idstate = s.idstate)
> ORDER BY s.name, c.name) AS T (s_name, c_name)
> GROUP BY T.s_name;
Note that this is nonstandard, but is an intentional (but I am not sure if
it's documented) feature of Postgres. There can be some similar situations
where you need to use OFFSET 0 to prevent optimizations that will break the
ordering.
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To: pgsql-sql@postgresql.org
Cc: bruno@wolff.to, yazicivo@ttnet.net.tr, everton.berz@gmail.com
Subject: Re: Sorting aggregate column contents
In-Reply-To: <20060503001602.GC31652@wolff.to>
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