X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 583EF9DC982 for ; Wed, 1 Mar 2006 20:37:36 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 42616-04 for ; Wed, 1 Mar 2006 20:37:39 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 358C29DC87A for ; Wed, 1 Mar 2006 20:37:34 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id k220bbbR017753 for ; Wed, 1 Mar 2006 19:37:37 -0500 (EST) To: pgsql-hackers@postgresql.org Subject: Re: [SQL] Interval subtracting In-reply-to: <44063632.20505@markdilger.com> References: <200603012326.k21NQOv08610@candle.pha.pa.us> <4406331A.6080307@markdilger.com> <17317.1141257505@sss.pgh.pa.us> <44063632.20505@markdilger.com> Comments: In-reply-to Mark Dilger message dated "Wed, 01 Mar 2006 16:02:58 -0800" Date: Wed, 01 Mar 2006 19:37:37 -0500 Message-ID: <17752.1141259857@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.111 required=5 tests=[AWL=0.111] X-Spam-Score: 0.111 X-Spam-Level: X-Archive-Number: 200603/90 X-Sequence-Number: 80488 Mark Dilger writes: > Tom Lane wrote: >> If so, one function or the other is cheating. > That depends what you mean by cheating. The justify_hours function > looks to see what answer justify_days would give, but does not > actually change the data. I described this all earlier and I still > don't see why there is anything wrong with it. The problem is that you can't determine "what answer justify_days would give" without using the assumption "1 month == 30 days", which is an assumption that justify_hours must not depend on. regards, tom lane