Skip site navigation (1) Skip section navigation (2)

Re: help on a query

From: Greg Stark <gsstark(at)mit(dot)edu>
To: mmurrain(at)dbdes(dot)com
Cc: "Thomas F(dot)O'Connell" <tfo(at)sitening(dot)com>,CHRIS HOOVER <CHRIS(dot)HOOVER(at)companiongroup(dot)com>, sad(at)bankir(dot)ru,pgsql-sql(at)postgresql(dot)org
Subject: Re: help on a query
Date: 2004-10-09 03:17:38
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-sql
Michelle Murrain <tech(at)murrain(dot)net> writes:

> The OUTER JOIN version is quite a bit more efficient (by an order of magnitude)
> than the option with WHERE NOT EXISTS subquery.

This is going to be heavily dependent on the version of postgres. IN/NOT IN
execution has improved a lot in 7.4 and later. If you're still on 7.3 then the
outer join will be better. But in 7.4 I would actually expect the NOT IN or
the NOT EXISTS to be faster.


In response to

pgsql-sql by date

Next:From: C. BensendDate: 2004-10-09 03:37:33
Subject: Impact of foreign keys on a simple count(*) ?
Previous:From: Michael FuhrDate: 2004-10-08 19:32:02
Subject: Re: Record Count

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group