Re: 3 value logic. Why is SQL so special?

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Tue, 19 Sep 2006 05:05:51 GMT
Message-ID: <PUKPg.22753$9u.271044@ursa-nb00s0.nbnet.nb.ca>

Chris Lim wrote:

> Bob Badour wrote:
>

>>SQL never will, which is ultimately why SQL is irrelevant.

>
> Then I guess your argument does not apply to databases using SQL (even
> though this is comp.databases.theory, I mistakenly thought you were
> talking about the real world, i.e. SQL).
>
> I don't know why you have dealt with so many people who have trouble
> with NULLs - to me this is a beginner's problem that is dealt with very
> easily.

I can only conclude that you are either a neophyte or a dilettante. The problems with NULL are legion and very well documented elsewhere.

NULL confuses reasonably intelligent people because it breaks important identities those people have been conditioned to expect such as:

SUM(A) + SUM(B) = SUM(A+B)

select sum(a) from atable;
select sum(b) from atable;
select sum(a+b) from atable;

In the presense of NULL, those queries violate the identity above. Received on Tue Sep 19 2006 - 00:05:51 CDT