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Message-ID: <bf05e51c0607130846ufdb8a31n5757f67361447c2b@mail.gmail.com>
Date: Thu, 13 Jul 2006 10:46:11 -0500
From: "Aaron Bono" <postgresql@aranya.com>
To: "Exner, Peter" <Exner@his.de>
Subject: Re: How to find entries missing in 2nd table?
Cc: "Richard Broersma Jr" <rabroersma@yahoo.com>,
	"SQL Postgresql List" <pgsql-sql@postgresql.org>
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On 7/12/06, Exner, Peter <Exner@his.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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On 7/12/06, <b class="gmail_sendername">Exner, Peter</b> &lt;<a href="mailto:Exner@his.de">Exner@his.de</a>&gt; wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br><br>what about<br><br>SELECT controller_id FROM control<br>WHERE controller_id NOT IN<br>(SELECT DISTINCT controller_id FROM datapack);</blockquote></div><br>The DISTINCT is not necessary.&nbsp; I have heard with Oracle that DISTINCT is a huge performance problem.&nbsp; Is that true on PostgreSQL also?
<br><br>==================================================================<br>&nbsp;&nbsp; Aaron Bono<br>&nbsp;&nbsp; Aranya Software Technologies, Inc.<br>&nbsp;&nbsp; <a href="http://www.aranya.com">http://www.aranya.com</a><br>==================================================================

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