Message-ID: <443B9624.2020503@logix-tt.com>
Date: Tue, 11 Apr 2006 13:42:28 +0200
From: Markus Schaber <schabi@logix-tt.com>
Organization: Logical Tracking and Tracing International AG, Switzerland
User-Agent: Debian Thunderbird 1.0.7 (X11/20051017)
MIME-Version: 1.0
To: Jeff Boes <jeff@endpoint.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Joins involving functions
References: <4436D343.5010802@endpoint.com>
In-Reply-To: <4436D343.5010802@endpoint.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

Hi, Jeff Boes,

Jeff Boes wrote:

> select * from bar
> cross join f_foo(bar.b) as foo;
> 
> Unfortunately, this last statement returns an error:
> 
> NOTICE:  adding missing FROM-clause entry for table "bar"
> ERROR:  function expression in FROM may not refer to other relations of
> same query level
> 
> Is there a method for joining function calls to tables? The only other
> approach I can think of is to write another function that returns "setof".

I don't exactly know what you want to achieve, so I'm just wildly guessing.

Do you really want the cross join between bar.* and f_foo(bar.b)?

If yes, use

SELECT x.b, y.b FROM bar x CROSS JOIN bar y;

If not, you maybe want

SELECT b, f_foo(b) FROM bar;

Or it may be you want something like:

SELECT * from bar CROSS JOIN (SELECT f_foo(bar.b) from bar) as foo ;


HTH,
Markus
-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf.     | Software Development GIS

Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org