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Message-ID: <87eeecff0506030744e04eb25@mail.gmail.com>
Date: Fri, 3 Jun 2005 17:44:59 +0300
From: Ami Ganguli <ami.ganguli@gmail.com>
Reply-To: Ami Ganguli <ami.ganguli@gmail.com>
To: pgsql-sql@postgresql.org
Subject: using a selected row as a function parameter
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Hi all,

I've been struggling with this for a while and haven't found anything
on the 'Net about it.  I've created a function that takes two table
rows as a parameters.  I'd like to use the output of a select (two
single rows) as the parameters, but I can't get it to work.  What am I
missing?

The function prototype looks like this:

CREATE OR REPLACE FUNCTION queue.apply_routing_rule(
                       queue.messages,=20
                       queue.routing_rules
                       ) RETURNS int2

and I would like to call it like this:

SELECT queue.apply_routing_rule(=20
                      (SELECT * from queue.messages WHERE id =3D 1),
                      (SELECT * from queue.routing_rules WHERE id =3D 1)
                      );

I get an error message along the lines of "sub-query must return a
single value".  I've tried different combinations of "CAST" and "ROW"
functions, but they give syntax errors.

Any suggestions?

Regards,
Ami.