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Re: char field <> or != to a value does not select where field is null ??? - Mailing list pgsql-bugs

From Tom Lane
Subject Re: char field <> or != to a value does not select where field is null ???
Date
Msg-id 1293.1127410697@sss.pgh.pa.us
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In response to char field <> or != to a value does not select where field is null ???  (Douglas Toltzman <doug@oakstreetsoftware.com>)
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Douglas Toltzman <doug@oakstreetsoftware.com> writes:
> It was my understanding that a NULL value would be not-equal to any
> non-null value.  Am I wrong about this?

Yes.  A NULL is neither equal nor unequal to anything else.

You can use IS DISTINCT FROM to get the behavior you are looking for,
but it might be better to rethink how you are using NULL.

            regards, tom lane

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