Re: 'fake' join and performance ?

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От Peter Galbavy
Тема Re: 'fake' join and performance ?
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Msg-id 000e01c279fc$7f33b5d0$10bc10ac@cblan.mblox.com
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Ответ на 'fake' join and performance ?  ("Peter Galbavy" <peter.galbavy@knowtion.net>)
Список pgsql-sql
> 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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