X-Original-To: pgsql-sql@postgresql.org
Received: from localhost (postgresql.org [64.49.215.8])
	by postgresql.org (Postfix) with ESMTP id 6659E475E6F
	for <pgsql-sql@postgresql.org>; Fri, 28 Feb 2003 17:17:54 -0500 (EST)
Received: from postgresql.org ([64.49.215.8])
	by localhost (postgresql.org [64.49.215.8:10024]) (amavisd-new) with
	SMTP id 43734-07 for <pgsql-sql@postgresql.org>;
	Fri, 28 Feb 2003 17:17:43 -0500 (EST)
Received: from news.hub.org (news.hub.org [64.49.215.80])
	by postgresql.org (Postfix) with ESMTP id 4A3D2474E42
	for <pgsql-sql@postgresql.org>; Fri, 28 Feb 2003 16:09:37 -0500 (EST)
Received: by news.hub.org (Postfix, from userid 8)
	id 357B043A611; Fri, 28 Feb 2003 16:09:37 -0500 (EST)
From: Dmitry Tkach <dmitry@openratings.com>
X-Newsgroups: comp.databases.postgresql.sql
Subject: Re: DELETE FROM  t WHERE EXISTS
Date: Fri, 28 Feb 2003 17:47:04 -0500
Organization: Hub.Org Networking Services (http://www.hub.org)
Lines: 43
Message-ID: <3E5FE6E8.9020200@openratings.com>
References: <3E5F530B.1649.424D34C1@localhost>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
X-Complaints-To: usenet@news.hub.org
To: Dan Langille <dan@langille.org>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021130
X-Accept-Language: en-us, en
In-Reply-To: <3E5F530B.1649.424D34C1@localhost>
To: pgsql-sql@postgresql.org
X-Virus-Scanned: by amavisd-new
X-Archive-Number: 200302/626
X-Sequence-Number: 12024

What about

select * into temp rows_to_keep from clp order by commit_date limit 100;
truncate clp;
insert into clp select * from rows_to_keep;

Dima.



Dan Langille wrote:
> Hi folks,
> 
> I wanted to delete "old" rows from a table.  These are the rows I 
> want to keep:
> 
> SELECT * 
> FROM clp 
> ORDER BY commit_date 
> LIMIT 100
> 
> So I tried this:
> 
> DELETE FROM clp 
> WHERE NOT EXISTS (
> SELECT * 
> FROM clp 
> ORDER BY commit_date 
> LIMIT 100);
> 
> Uhh uhh, nothing deleted.  I don't understand why.
> 
> OK, I can do this instead:
> 
> DELETE from clp 
> where commit_log_id NOT in (
> SELECT commit_log_id 
> FROM clp 
> ORDER BY commit_date 
> LIMIT 100);
> 
> Can you think of a better way?