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From: Mike Rylander <mrylander@gmail.com>
To: cristivoinicaru <cristivoinicaru@dmhi.ct.ro>
Cc: pgsql-sql@postgresql.org
Subject: Re: sql
Date: Mon, 25 Oct 2004 07:20:22 -0400
Message-ID: <b918cf3d041025042021ca123e@mail.gmail.com> (raw)
In-Reply-To: <013901c4ba6a$8771d320$7202a8c0@aaa>
References: <013901c4ba6a$8771d320$7202a8c0@aaa>

On Mon, 25 Oct 2004 10:13:37 +0200, cristivoinicaru
<cristivoinicaru@dmhi.ct.ro> wrote:
> I have a postgres table like this:
> 
> CREATE TABLE "temp50" (
>  "gc" character varying(36),
>  "co" character varying(7),
>  "data" date,
>  "ora" smallint
> 
> );
> 
> It contains the following records:
> 
> 5003707G9G9419 22012BB 10-14-2004 82
> 5003707G9G9419 22012BC 10-14-2004 44
> 5003707G9G9419 22022BB 10-14-2004 82
> 5003707G9G9420 22022BC 10-18-2004 49
> 
> I'd  like the result of the sql interogation to be like this:
> 
> 5003707G9G9419 22012BB 10-14-2004 82
> 5003707G9G9420 22022BC 10-18-2004 49
> 
> Explanations:
> I want like sql interogation to select only one record from each "gc" group
> record (who has the same code "gc" (that means that the "gc" field will be
> unique key)) with the following two condition:
> 1)from each "gc" group of records to select the record who has the value of
> "ora" field maxim.
> 2)if two ore more record have the same value of the maxim value of the "ora"
> to select oly one of them

Try:

SELECT * FROM temp50 GROUP BY gc ORDER BY ora DESC;


--miker

> 
> Thanks!
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 8: explain analyze is your friend
>



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