Received: from maggie.eskom.co.za (mail-spool2-1.eskom.co.za [147.110.52.115]) by mail.postgresql.org (8.11.1/8.11.1) with ESMTP id eA27F7l22040 for ; Thu, 2 Nov 2000 02:15:14 -0500 (EST) (envelope-from Marc.Rohloff@eskom.co.za) Received: from eskom.co.za (gw.eskom.co.za [147.110.52.108]) by maggie.eskom.co.za (8.11.1/8.11.1/check_local4.1) with SMTP id eA27Ehj29337 for ; Thu, 2 Nov 2000 09:14:43 +0200 X-Spam-Filter: check_local by digitalanswers.org Received: from ROUTING-Message_Server by eskom.co.za with Novell_GroupWise; Thu, 02 Nov 2000 09:14:43 +0200 Message-Id: X-Mailer: Novell GroupWise Internet Agent 5.5.3.1 Date: Thu, 02 Nov 2000 09:11:50 +0200 From: "Marc Rohloff" To: , Subject: Re: Outer Joins Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.postgresql.org id eA27GAl22059 X-Archive-Number: 200011/11 X-Sequence-Number: 42 >> select a.col1, b.col2 from a,b >> where a.col1 = b.col2 >> or a.col1 not in (select b.col2 from b) >This would work, but it would be *much* slower than a UNION query. "Not >In" queries are perhaps the slowest you can run; see the earlier thread >"Query Problem" for a discussion. UNION queries are, in fact, very fast >... just awkward to code and manipulate. Why should this be slower since the UNION Query still has an identical not in clause? This is far easier (for me) to read. Marc