Date: Sat, 11 Mar 2006 17:43:37 +0100
From: Andreas Kretschmer <akretschmer@spamfence.net>
To: pgsql-sql@postgresql.org
Subject: Re: Merging rows into one result?
Message-ID: <20060311164337.GA19131@KanotixBox>
References: <20060311173133.1358a018@io.solnet>
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Jesper K. Pedersen <jkp@solnet.homeip.net> schrieb:

> Is it possible to use SQL to merge data into one result?
> 
> A theorethical example to explain:
> 
> tbl_test (
>   id integer,
>   information varchar(25))
> 
> id | information
> ---+--------------
> 1  | Yo
> 2  | Go away
> 1  | Stay put
> 3  | Greetings
> 
> Please note id is not unique and not a primary key.
> 
> and I wonder if there is any functions to "merge" data (sort of
> concat'ing).
> A normal: select information from tbl_test where id=1
> would result in the rows
>  Yo
>  Stay put
> 
> I would like a single row result in the format of:
>  Yo Stay put

Yes, of corse, this is possible. You need a own aggregate-function. A
similar example for this task can you find here:

http://www.zigo.dhs.org/postgresql/#comma_aggregate

I think, it is very simple to rewrite this example for your purpose.


HTH, Andreas
-- 
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