Re: not null - trivial, unexpected behavior

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: <john(at)august(dot)com>
Cc: <pgsql-sql(at)postgresql(dot)org>
Subject: Re: not null - trivial, unexpected behavior
Date: 2001-06-16 16:23:35
Message-ID: Pine.LNX.4.30.0106161820100.755-100000@peter.localdomain
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I wrote:

[ x = NULL vs. x != NULL ]
> > What am i missing? Shouldn't those two sets be complimentary?
>
> They should.

Correction: Each Boolean expression can have one of *three* values: true,
false, unknown (null). So those two sets will not be "complimentary" in
the traditional sense because both expressions _should_ (modulo the
information I pointed you to) return "unknown".

--
Peter Eisentraut peter_e(at)gmx(dot)net http://funkturm.homeip.net/~peter

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