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Re: IS NOT NULL and LEFT JOIN - Mailing list pgsql-performance

From Tom Lane
Subject Re: IS NOT NULL and LEFT JOIN
Date
Msg-id 3181.1413813488@sss.pgh.pa.us
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In response to Re: IS NOT NULL and LEFT JOIN  (Laurent Martelli <laurent.martelli@enercoop.org>)
Responses Re: IS NOT NULL and LEFT JOIN
Re: IS NOT NULL and LEFT JOIN
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Laurent Martelli <laurent.martelli@enercoop.org> writes:
> Do we agree that both queries are identical ?

No, they *aren't* identical.  Go consult any SQL reference.  Left join
conditions don't work the way you seem to be thinking: after the join,
the RHS column might be null, rather than equal to the LHS column.

            regards, tom lane

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