> Could someone explain to me why not eliminating nulls destroys the
> potential results of the query ? In other words, for any X not null, X
> not in (some NULLs) is false.
You already know the answer: comparisons to NULL always evaluate to
false. You may conclude that this exposes a flaw in SQL9x's definition
of three-value logic, but is the result you should expect for a
standards-compliant SQL implementation.
(I was going to say "almost always" rather than "always" but I'm not
recalling a counter example and don't have time to look it up. Sorry
about that... ;)
In response to
pgsql-hackers by date
|Next:||From: Tom Lane||Date: 2000-12-29 23:43:38|
|Subject: Re: GNU readline and BSD license |
|Previous:||From: Tom Lane||Date: 2000-12-29 22:41:25|
|Subject: Regress-test failure in current sources|