> > > Would it be worth replacing the condition with the equivalent? > I mean would that help optimizing better some queries when it knows that a > is (not) nullable or when "a" is more complicated expression? > > a <> a : (a IS NULL) AND NULL > a = a : (a IS NOT NULL) OR NULL >
I think you're looking for a IS DISTINCT FROM a And that will work for cases where a might be null. I have no opinion about whether adding such a test to the planner is worth it.