Date: Mon, 28 Sep 2009 12:27:16 +0100
From: David W Noon <dwnoon@ntlworld.com>
To: pgsql-sql@postgresql.org
Subject: Re: simple (?) join
Message-ID: <20090928122716.61b99cfb@dwnoon.ntlworld.com>
In-Reply-To: <200909281202.20768.gary.stainburn@ringways.co.uk>
References: <200909241616.36933.gary.stainburn@ringways.co.uk>
	<20090926205349.5fa284f1@dwnoon.ntlworld.com>
	<4ABE7669.50001@emproshunts.com>
	<200909281202.20768.gary.stainburn@ringways.co.uk>
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On Mon, 28 Sep 2009 12:02:20 +0100, Gary Stainburn wrote about Re:
[SQL] simple (?) join:

[snip]
>For some reason the reply I sent on Friday didn't get through.
>What I need is all of the order record and all of the latest log entry 
>returning as a join. Specifically I want for each order the most
>recent log entry timestamp and it's associated user - i.e. who made
>the the last log entry and when.

In that case, try this:

SELECT o.*, ol.ol_timestamp, ol.ol_user
FROM orders AS o
INNER JOIN orders_log AS ol
ON ol.o_id = o.o_id
WHERE ol.ol_timestamp = (SELECT MAX(ol_timestamp) FROM orders_log AS
   ol2 WHERE ol2.o_id = o.o_id);

This will omit orders that have never been logged. You have not
specified what you want done with them.
-- 
Regards,

Dave  [RLU #314465]
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david.w.noon@ntlworld.com (David W Noon)
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