Message-ID: <3DC00823.7396E79C@nsd.ca>
Date: Wed, 30 Oct 2002 11:26:11 -0500
From: Jean-Luc Lachance <jllachan@nsd.ca>
MIME-Version: 1.0
To: Josh Berkus <josh@agliodbs.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-sql@postgresql.org
Subject: Re: BOOLEAN question
References: <web-1804001@davinci.ethosmedia.com>
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Why not simply:

SELECT COALESCE( (SELECT true FROM ... WHERE boolcol LIMIT 1), FALSE);

JLL

Josh Berkus wrote:
> 
> Tom,
> 
> > Perhaps
> >       SELECT true = ANY (SELECT boolcol FROM ...);
> > or
> >       SELECT true IN (SELECT boolcol FROM ...);
> >
> > Which is not to say that MAX(bool) might not be a nicer solution;
> > but you can definitely do it with SQL-spec constructs.
> 
> Based on some rough testing,
> 
> SELECT true = ANY ( SELECT boolcol FROM complex query )
> 
> Is marginlly faster than
> 
> SELECT max(boolcol) FROM complex query
> 
> With a custom MAX(boolean) function.
> 
> So I'll stick to ANY().
> 
> -Josh
> 
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