Question about antijoin - Mailing list pgsql-general

From dandl
Subject Question about antijoin
Date
Msg-id 002801d1dc29$fa2a96c0$ee7fc440$@andl.org
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Responses Re: Question about antijoin
Re: Question about antijoin
List pgsql-general
>    NOT EXISTS (SELECT NULL FROM dyr_pause_mot WHERE avlsnr = a.avlsnr)
>
> This can be executed as anti-join and is often more efficient.

This got my interest! It's of great interest to me to know how and when Postgres performs an anti-join (this being a
significantomission from SQL). 

Is this a reliable trigger: (NOT EXISTS <subselect>)?

Regards
David M Bennett FACS

Andl - A New Database Language - andl.org







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