Re: Plan for outer joins

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От Martijn van Oosterhout
Тема Re: Plan for outer joins
Дата
Msg-id 20060911100545.GC16564@svana.org
обсуждение исходный текст
Ответ на Plan for outer joins  (Alban Hertroys <alban@magproductions.nl>)
Ответы Re: Plan for outer joins  (Alban Hertroys <alban@magproductions.nl>)
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On Mon, Sep 11, 2006 at 11:58:56AM +0200, Alban Hertroys wrote:
> Hi,
>
> I was tuning a join on a few tables for a SELECT COUNT(*) query, when I
> realized that the content of the second table didn't actually matter to
> the count. So, I figured a LEFT OUTER JOIN would be faster, but...
> apparently it's not.

Well, it would matter if the outer side of the join could return more
than one row. You may know that won't happen, but the database may not.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
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