From: | "Nate Teller" <nate(dot)teller(at)mindspring(dot)com> |
---|---|
To: | "Aaron Bono" <postgresql(at)aranya(dot)com>, "Exner, Peter" <Exner(at)his(dot)de> |
Cc: | "Richard Broersma Jr" <rabroersma(at)yahoo(dot)com>, "SQL Postgresql List" <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: How to find entries missing in 2nd table? |
Date: | 2006-07-17 01:09:48 |
Message-ID: | JOEPKPKCCCBGEIEIKIIPCEHCDAAA.nate.teller@mindspring.com |
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Thread: | |
Lists: | pgsql-sql |
I have received good performance with the following:
select c.controller
from control c
left outer join datapack d on d.controller_id = c.controller_id
where d.controller_id is null
Nate Teller
-----Original Message-----
From: pgsql-sql-owner(at)postgresql(dot)org
[mailto:pgsql-sql-owner(at)postgresql(dot)org]On Behalf Of Aaron Bono
Sent: Thursday, July 13, 2006 11:46 AM
To: Exner, Peter
Cc: Richard Broersma Jr; SQL Postgresql List
Subject: Re: [SQL] How to find entries missing in 2nd table?
On 7/12/06, Exner, Peter < Exner(at)his(dot)de <mailto:Exner(at)his(dot)de> > wrote:
Hi,
what about
SELECT controller_id FROM control
WHERE controller_id NOT IN
(SELECT DISTINCT controller_id FROM datapack);
The DISTINCT is not necessary. I have heard with Oracle that DISTINCT is a
huge performance problem. Is that true on PostgreSQL also?
==================================================================
Aaron Bono
Aranya Software Technologies, Inc.
http://www.aranya.com
==================================================================
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