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From: Ian Barwick <barwick@gmx.net>
Organization: akademie.de
To: "Albrecht Berger" <berger1517@gmx.ch>, "pgsql" <pgsql-sql@postgresql.org>
Subject: Re: replace null with 0 in subselect ?
Date: Wed, 16 Oct 2002 14:16:08 +0200
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On Wednesday 16 October 2002 12:07, Albrecht Berger wrote:
> Hello,
> I have a statement like this :
>
> INSERT INTO tab1 (c1, c2, c3) VALUES (1,2, SELECT MAX(pos)+1 FROM tab2);
>
> This works fine if the subselect returns a value, but if it returns
> null there is a problem. In this case a 0 has to be inserted.
> Is there any pg function which solves this problem ?
> I know that oracle has a function but I didn't find
> something similar in pg.

A quick and dirty solution (untested):

INSERT INTO tab1 (c1, c2, c3) 
VALUES (1,2, 
 (SELECT CASE WHEN (SELECT MAX(pos)+1 ) IS NULL THEN 0
  ELSE (SELECT MAX(pos)+1 )
  END)
)


Ian Barwick
barwick@gmx.net