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Re: null != null ???

From: "Brett W(dot) McCoy" <bmccoy(at)chapelperilous(dot)net>
To: Fran Fabrizio <ffabrizio(at)mmrd(dot)com>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: Re: null != null ???
Date: 2001-10-26 18:37:10
Message-ID: Pine.LNX.4.30.0110261434180.2640-100000@chapelperilous.net (view raw or flat)
Thread:
Lists: pgsql-general
On Fri, 26 Oct 2001, Fran Fabrizio wrote:

> I have a situation where the left and right side of a where clause both
> evaluate to null independently, but when compared to
> each other, they don't equate.  Observe:

It seems to me that a null value cannot be compared to a null value
because NULL means 'no value' -- it would be like comparing two undefined
variables in Perl (undef) or two NULL pointers in C.  It will never be
true because you can't equate nothing to nothing.

-- Brett
                                          http://www.chapelperilous.net/
------------------------------------------------------------------------
God created a few perfect heads.  The rest he covered with hair.


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