Re: 'fake' join and performance ?

From: "Peter Galbavy" <peter(dot)galbavy(at)knowtion(dot)net>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-sql(at)postgresql(dot)org>
Subject: Re: 'fake' join and performance ?
Date: 2002-10-22 18:54:47
Message-ID: 000e01c279fc$7f33b5d0$10bc10ac@cblan.mblox.com
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> That would be in violation of the SQL spec. The query is defined to
> return each join row from the cross product of the FROM tables that
> meets the condition of the WHERE clause. As you wrote the query, each
> metadata row that meets the WHERE clause will be returned exactly as
> many times as there are rows in the images table. There is no such
> thing as an "unreferenced" FROM entry as far as SQL is concerned.

Sounds about right. Thanks for the clarification.

Peter

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