From: Richard Huxton <dev@archonet.com>
To: chester c young <chestercyoung@yahoo.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: broken join optimization? (8.0)
Date: Wed, 26 Oct 2005 09:31:48 +0100
Message-ID: <435F3EF4.7010808@archonet.com> (raw)
In-Reply-To: <20051025235612.20767.qmail@web54301.mail.yahoo.com>
References: <20051025235612.20767.qmail@web54301.mail.yahoo.com>
chester c young wrote:
> in php (for example) it's frequently nice to get the structure of a
> table without any data, ie, pull a single row with each attribute's
> value is null. I use the query (dual is a table of one row ala
> Oracle):
>
> select m.* from dual
> left join mytable m on( false );
Out of curiosity, why do it this way? Does "rownum" not get set if there
are no rows returned?
Actually, even if it doesn't why not use:
SELECT * FROM mytable WHERE true=false
Surely your client interface returns the types/column-names then? It
should - that's a set of 0 rows.
--
Richard Huxton
Archonet Ltd
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To: pgsql-sql@postgresql.org
Cc: dev@archonet.com, chestercyoung@yahoo.com
Subject: Re: broken join optimization? (8.0)
In-Reply-To: <435F3EF4.7010808@archonet.com>
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