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* Concatenate strings using GROUP BY
@ 2006-02-09 09:35 Philippe Lang <philippe.lang@attiksystem.ch>
0 siblings, 1 reply; 2+ messages in thread
From: Philippe Lang @ 2006-02-09 09:35 UTC (permalink / raw)
To: pgsql-sql
Hi,
Let's say we have a query like:
SELECT id, fk, str
FROM foo
... which returns:
id fk str
---------------
1 1 a
2 1 b
3 2 c
Is there a pure SQL way of contactenating str values into a single string,
and get instead:
id fk str
---------------
1 1 a/b
2 12 c
I was thinking of something like:
SELECT id, fk, CONCAT(str || '/')
FROM FOO
GROUP BY fk
Do we have to use PL/PGSQL for that?
Thanks,
----------------------------------
Philippe Lang, Ing. Dipl. EPFL
Attik System
rte de la Fonderie 2
1700 Fribourg
Switzerland
http://www.attiksystem.ch
Tel: +41 (26) 422 13 75
Fax: +41 (26) 422 13 76
Email: philippe.lang@attiksystem.ch
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* Re: Concatenate strings using GROUP BY
@ 2006-02-09 09:52 A. Kretschmer <andreas.kretschmer@schollglas.com>
parent: Philippe Lang <philippe.lang@attiksystem.ch>
0 siblings, 0 replies; 2+ messages in thread
From: A. Kretschmer @ 2006-02-09 09:52 UTC (permalink / raw)
To: pgsql-sql
am 09.02.2006, um 10:35:03 +0100 mailte Philippe Lang folgendes:
> id fk str
> ---------------
> 1 1 a
> 2 1 b
> 3 2 c
>
> Is there a pure SQL way of contactenating str values into a single string,
> and get instead:
>
> id fk str
> ---------------
> 1 1 a/b
> 2 12 c
>
> I was thinking of something like:
>
> SELECT id, fk, CONCAT(str || '/')
> FROM FOO
> GROUP BY fk
>
> Do we have to use PL/PGSQL for that?
Yes, you need a new aggregate function.
http://www.postgresql.org/docs/8.0/interactive/xaggr.html
HTH, Andreas
--
Andreas Kretschmer (Kontakt: siehe Header)
Heynitz: 035242/47215, D1: 0160/7141639
GnuPG-ID 0x3FFF606C http://wwwkeys.de.pgp.net
=== Schollglas Unternehmensgruppe ===
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2006-02-09 09:35 Concatenate strings using GROUP BY Philippe Lang <philippe.lang@attiksystem.ch>
2006-02-09 09:52 ` A. Kretschmer <andreas.kretschmer@schollglas.com>
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