X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.2]) by svr1.postgresql.org (Postfix) with ESMTP id E89DBD1B169 for ; Wed, 19 May 2004 05:55:45 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (neptune.hub.org [200.46.204.2]) (amavisd-new, port 10024) with ESMTP id 06183-09 for ; Wed, 19 May 2004 05:55:28 -0300 (ADT) Received: from fzkmail2.fzk.de (fzkmail2.fzk.de [141.52.27.52]) by svr1.postgresql.org (Postfix) with SMTP id 1F225D1B21B for ; Wed, 19 May 2004 05:55:24 -0300 (ADT) Received: FROM resy5.fzk.de BY fzkmail2.fzk.de ; Wed May 19 10:55:23 2004 +0200 Received: œby rodos.fzk.de with ESMTP (8.8.6 (PHNE_17135)/8.7.1) id KAA17406; Wed, 19 May 2004 10:55:23 +0200 (METDST) From: Christoph Haller Message-Id: <200405190855.KAA02721@rodos> Subject: Re: a wierd query To: s.vanroye@farcourier.com (Stijn Vanroye) Date: Wed, 19 May 2004 10:55:22 METDST Cc: pgsql-sql@postgresql.org In-Reply-To: <71E201BE5E881C46811BA160694C5FCB046739@fs1000.farcourier.com>; from "Stijn Vanroye" at May 17, 104 11:35 am X-Mailer: Elm [revision: 212.4] X-Virus-Scanned: by amavisd-new at postgresql.org X-Amavis-Alert: BAD HEADER Non-encoded 8-bit data (char 9C hex) in message header 'Received' Received: \234by rodos.fzk.de... ^ X-Spam-Status: No, hits=0.0 tagged_above=0.0 required=5.0 tests= X-Spam-Level: X-Archive-Number: 200405/161 X-Sequence-Number: 17875 > > select distinct on (date, employee_id) employee_id, date from > ( > select distinct on (begindate, employee_id) begindate as date, employ= > ee_id from workhour > UNION > select distinct on (enddate, employee_id) enddate as date, employee_i= > d from workhour > )as dist > > Just as a side note If you don't use ORDER BY when using DISTINCT ON you'll have unpredictable results. Regards, Christoph