Date: Sat, 26 Sep 2009 20:53:49 +0100
From: David W Noon <dwnoon@ntlworld.com>
To: pgsql-sql@postgresql.org
Subject: Re: simple (?) join
Message-ID: <20090926205349.5fa284f1@dwnoon.ntlworld.com>
In-Reply-To: <4ABE6360.20205@emproshunts.com>
References: <200909241616.36933.gary.stainburn@ringways.co.uk>
	<20090924194629.44bc236f@dwnoon.ntlworld.com>
	<4ABBD34B.9080600@emproshunts.com>
	<20090924222106.23a5c1f3@dwnoon.ntlworld.com>
	<4ABE6360.20205@emproshunts.com>
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On Sat, 26 Sep 2009 14:54:24 -0400, justin wrote about Re: [SQL] simple
(?) join:

[snip]
>Quoting Gary
>"How can I select all from orders and the last (latest) entry from the 
>orders_log?"

In that case, a simple Cartesian product will do:

SELECT o.*, maxi.ts
FROM orders AS o,
(SELECT MAX(ol_timestamp) AS ts FROM orders_log) AS maxi;

Since the cardinality of the subquery "maxi" is 1, it will give a result
set with cardinality of the complete orders table.

I don't understand why anybody would want to do that. [De gustibus ... ]
-- 
Regards,

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