Re: [PERFORM] Optimization inner join - Mailing list pgsql-performance

On Jan 19, 2017, at 08:30, Vitalii Tymchyshyn <vit@tym.im> wrote:

Hi.

In SQL "null == any value" resolves to false, so optimizer can safely skip nulls from either side if any for the inner join.

Best regards, Vitalii Tymchyshyn

NULL is still a value that may be paired with a NULL in a.a

The only optimization I could see is if the a.a column has NOT NULL defined while b.b does not have NOT NULL defined.

Not sure if it is all that common. Curious what if you put b.b IS NOT NULL in the WHERE statement?

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Phillip Couto