[samatman]

This is basically the correct take, but I would say that NULL is a real and useful concept which databases should have.

That implies that comparison and boolean operators should be ternary, which would be ugly and confusing: but an ugly and confusing that reflects reality.

This would give us three "greater than" operators:

   WHERE col1  > col2
   WHERE col1 ?> col2
   WHERE col1 >? col2

The first is always false for NULL, the second always picks the NULL column, the third never picks the NULL column. It doesn't seem coherent to order two NULLs, so that would always be false. I'm not attached to the syntax, which is intended to be illustrative.

The most important of such operators would be

   WHERE col1 ?= col2

which coerces two NULLs to be equivalent. It says "yes NULLs aren't comparable, but for this query, I want to treat them as equal". Because that is only usually true, not invariably so.