Date: Wed, 9 May 2007 16:30:21 +0200
From: Louis-David Mitterrand <vindex+lists-pgsql-sql@apartia.org>
To: pgsql-sql@postgresql.org
Subject: Re: query to select a linked list
Message-ID: <20070509143021.GA20210@apartia.fr>
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References: <20070509125520.GA17497@apartia.fr>
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On Wed, May 09, 2007 at 02:55:20PM +0200, Louis-David Mitterrand wrote:
> Hi,
> 
> To build a threaded forum application I came up the following schema:
> 
> forum
> ------
> id_forum | integer| not null  default nextval('forum_id_forum_seq'::regclass)
> id_parent| integer| 
> subject  | text   | not null
> message  | text   | 
> 
> Each message a unique id_forum and an id_parent pointing to the replied 
> post (empty if first post).
> 
> How can I build an elegant query to select all messages in a thread?

I am trying to write a recursive pl/sql function to return all thread 
children:

create or replace function forum_children(integer) returns setof forum as $$
declare
    rec record;
begin

    for rec in select * from forum where $1 in (id_parent,id_forum) loop

        select * from forum_children(rec.id_forum);
        return next rec;

    end loop;

    return;

end;
$$ language 'plpgsql';


But it does not work as intended (infinite loop?).

What did I miss?