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Message-ID: <b918cf3d04102506056ead8820@mail.gmail.com>
Date: Mon, 25 Oct 2004 09:05:39 -0400
From: Mike Rylander <mrylander@gmail.com>
Reply-To: Mike Rylander <mrylander@gmail.com>
To: akopciuch@bddf.ca
Subject: Re: sql
Cc: pgsql-sql@postgresql.org
In-Reply-To: <200410250544.06403.akopciuch@bddf.ca>
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References: <013901c4ba6a$8771d320$7202a8c0@aaa>
	<b918cf3d041025042021ca123e@mail.gmail.com>
	<200410250544.06403.akopciuch@bddf.ca>

On Mon, 25 Oct 2004 05:44:06 -0600, Andrew J. Kopciuch
<akopciuch@bddf.ca> wrote:
> On Monday 25 October 2004 05:20, Mike Rylander wrote:
> > SELECT * FROM temp50 GROUP BY gc ORDER BY ora DESC;
> 
> You can not have have expressions (columns etc.) in the SELECT list that are
> either not in a GROUP BY clause, or used in an aggregate function when you
> use GROUP BY in the statement.  By saying SELECT *, means you would have to
> GROUP BY gc, co, data, ora ...

Doh!  Of course.   Should have had coffee before writing that ;)

> 
> That isn't going to do what he wants.  And the SQL you stated should give you
> an error:
> 
> ERROR:  column "temp50.co" must appear in the GROUP BY clause or be used in an
> aggregate function
> 
> What he wants to do is use DISTINCT ON:
> 
> SELECT DISTINCT ON (gc) gc, co, data, ora FROM temp50 ORDER BY gc, ora DESC;
> 
> Andy
>