Reece Hart <reece@harts.net> writes:
> However, it's not clear that you've considered a clause like 'ORDER BY
> (foo IS NULL), foo', which I believe is not implementation dependent.
Yeah, that should work reasonably portably ... where "portable" means
"equally lousy performance in every implementation", unfortunately :-(.
I rather doubt that many implementations will see through that to decide
that they can avoid an explicit sort.
> (In SQL2003 draft, true is defined to sort before false. I can't find a
> similar statement in SQL92 or SQL99.)
SQL92 doesn't actually acknowledge boolean as a data type, so it's not
gonna say that; but SQL99 does, and it has
The value true_ is greater than the value false_
under 4.6.1 Comparison and assignment of booleans
regards, tom lane
