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Date: Sat, 24 Mar 2007 14:07:59 +0100
From: Martijn van Oosterhout <kleptog@svana.org>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org,
	pgsql-performance@postgresql.org,
	Andrea Olson <Aolson.CCAP.Courts@wicourts.gov>,
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	John Hutchins <jhutchi.CCAP.Courts@wicourts.gov>,
	Randy Peterson <RPETERS.CCAP.Courts@wicourts.gov>,
	Shannon Spranger <ssprang.CCAP.Courts@wicourts.gov>
Subject: Re: EXISTS optimization
Message-ID: <20070324130759.GA1089@svana.org>
Reply-To: Martijn van Oosterhout <kleptog@svana.org>
References: <4603C1A3.EE98.0025.0@wicourts.gov>
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On Fri, Mar 23, 2007 at 05:30:27PM -0500, Kevin Grittner wrote:
> I don't understand -- TRUE OR UNKNOWN evaluates to TRUE, so why would
> the IN need to continue?  I'm not quite following the rest; could you
> elaborate or give an example?  (Sorry if I'm lagging behind the rest
> of the class here.)

You're right, I'm getting confused with the interaction of NULL and NOT
IN.

The multiple evaluation thing still applies, but that's minor.

Have a nice day,
--=20
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to l=
itigate.

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