From: | Jean-Luc Lachance <jllachan(at)nsd(dot)ca> |
---|---|
To: | Josh Berkus <josh(at)agliodbs(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-sql(at)postgresql(dot)org |
Subject: | Re: BOOLEAN question |
Date: | 2002-10-30 16:26:11 |
Message-ID: | 3DC00823.7396E79C@nsd.ca |
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Lists: | pgsql-sql |
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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