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@gmx.net http://funkturm.homeip.net/~peter