Re: Does Codd's view of a relational database differ from that ofDate& Darwin? [M.Gittens]
From: mountain man <hobbit_at_southern_seaweed.com.op>
Date: Tue, 07 Jun 2005 09:32:44 GMT
Message-ID: <0Rdpe.6593$F7.2252_at_news-server.bigpond.net.au>
Date: Tue, 07 Jun 2005 09:32:44 GMT
Message-ID: <0Rdpe.6593$F7.2252_at_news-server.bigpond.net.au>
"Paul" <paul_at_test.com> wrote:
> Here's some discussion of a very concrete example of a NULL problem in
> SQL: http://www.firstsql.com/iexist2.htm
>
> The author says that his RDBMS solves this problem though, and that is
> just a problem with SQL and NULLs, not with the relational model and
> NULLs.
>
> Are there any rebuttals of this claim that anyone has?
The original query may be written as follows without the sub-select statement, and has no problems with the null.
select distinct spx.sno
from sp spx
where spx.pno = 'P1'
and spx.qty <> 1000
-- Pete Brown IT Managers & Engineers Falls Creek Australia www.mountainman.com.auReceived on Tue Jun 07 2005 - 11:32:44 CEST