Re: join and query planner

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От Stephan Szabo
Тема Re: join and query planner
Дата
Msg-id 20050706152750.V50953@megazone.bigpanda.com
обсуждение исходный текст
Ответ на join and query planner  ("Dario" <dario_d_s@unitech.com.ar>)
Список pgsql-performance
On Wed, 6 Jul 2005, Dario wrote:

>
> (first at all, sorry for my english)
> Hi.
>    - Does "left join" restrict the order in which the planner must join
> tables? I've read about join, but i'm not sure about left join...

Yes. Reordering the outer joins can change the results in some cases which
would be invalid.  Before we can change the ordering behavior, we really
need to know under what conditions it is safe to do the reordering.


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