Re: Sheer logical inconsistencies (of optimizer??)

Posted in 2006

Ulrich Mueller — Wed, 17 May 2006 13:28:01 +0200 (MEST) — source: Usenet: comp.databases.informix

> > > > that way it would still conform to > > mathematical relation properties with NULL values, > > Please explain? > relation ~R on set M is a subset A of MxM, we write x ~R y iff (x,y) is element of A, as I suppose, x ~R NULL is never true, but there IS a difference between SQL interpretation NOT (age>=21) and (age<21) OR age IS NULL (I just checked with mysql, the same problem, so this is not really Informix topic, excuse me please, but comments still welcome)