Received: from localhost (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 0ACC6475FBF for ; Tue, 22 Oct 2002 14:54:43 -0400 (EDT) Received: from mailstore-1.mail.knowledge.com (frida.london.knowtion.net [213.170.2.69]) by postgresql.org (Postfix) with ESMTP id 5F356475458 for ; Tue, 22 Oct 2002 14:54:42 -0400 (EDT) Received: from adsl-solo-40-176.claranet.co.uk ([213.253.40.176] helo=petergalbavy) by mailstore-1.mail.knowledge.com with asmtp (Exim 3.33 #1) id 1844As-0005G2-00; Tue, 22 Oct 2002 19:54:42 +0100 Message-ID: <000e01c279fc$7f33b5d0$10bc10ac@cblan.mblox.com> From: "Peter Galbavy" To: "Tom Lane" Cc: References: <054501c279e5$8bfcfe00$4528a8c0@cblan.mblox.com> <24033.1035308365@sss.pgh.pa.us> Subject: Re: 'fake' join and performance ? Date: Tue, 22 Oct 2002 19:54:47 +0100 Organization: Knowtion Ltd. MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Virus-Scanned: by AMaViS new-20020517 X-Archive-Number: 200210/284 X-Sequence-Number: 10001 > That would be in violation of the SQL spec. The query is defined to > return each join row from the cross product of the FROM tables that > meets the condition of the WHERE clause. As you wrote the query, each > metadata row that meets the WHERE clause will be returned exactly as > many times as there are rows in the images table. There is no such > thing as an "unreferenced" FROM entry as far as SQL is concerned. Sounds about right. Thanks for the clarification. Peter