Re: Order By for aggregate functions (Simulating Group_concat)

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От Martijn van Oosterhout
Тема Re: Order By for aggregate functions (Simulating Group_concat)
Дата
Msg-id 20050901151441.GD28062@svana.org
обсуждение исходный текст
Ответ на Order By for aggregate functions (Simulating Group_concat)  (Charlotte Pollock <c.pollock@bangor.ac.uk>)
Ответы Re: Order By for aggregate functions (Simulating Group_concat)  (Michael Fuhr <mike@fuhr.org>)
Список pgsql-general
On Thu, Sep 01, 2005 at 10:04:12AM +0100, Charlotte Pollock wrote:
> Hi All
>
> I'm trying to create a aggregate function similar 9but not identical) to
> mysql's group_concat.
>
> What I want to be able to do is pass and order by field to the aggregate so
> I can be certain I get the list of strings in the correct order.

Order them before the aggregate?

SELECT aggregate(field) FROM (SELECT field FROM xxx ORDER BY wherever) x;

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.

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