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RE: [HACKERS] RE: [GENERAL] Long update query ? (also Re: [GENERAL] CNF vs. DNF)

From: "Taral" <taral(at)mail(dot)utexas(dot)edu>
To: "Bruce Momjian" <maillist(at)candle(dot)pha(dot)pa(dot)us>, <jwieck(at)debis(dot)com>
Cc: <hackers(at)postgreSQL(dot)org>
Subject: RE: [HACKERS] RE: [GENERAL] Long update query ? (also Re: [GENERAL] CNF vs. DNF)
Date: 1998-10-02 21:12:19
Message-ID: 000001bdee49$56c7cd40$3b291f0a@taral (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackers
> Another idea is that we rewrite queries such as:
>
> 	SELECT *
> 	FROM tab
> 	WHERE (a=1 AND b=2 AND c=3) OR
> 	      (a=1 AND b=2 AND c=4) OR
> 	      (a=1 AND b=2 AND c=5) OR
> 	      (a=1 AND b=2 AND c=6)
>
> into:
>
> 	SELECT *
> 	FROM tab
> 	WHERE (a=1 AND b=2) AND (c=3 OR c=4 OR c=5 OR c=6)

Very nice, but that's like trying to code factorization of numbers... not
pretty, and very CPU intensive on complex queries...

Taral


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