I often accidentally write SELECT .. WHERE .. WHERE ..;
which is obviously wrong, but what I mean when I do this is SELECT .. WHERE .. AND ..; and if I wrote GROUP BY .. HAVING queries as often as I do ones that don't GROUP BY then I'd probably also accidentally use extra HAVINGs as ANDs. It doesn't seem too crazy that extra WHEREs in WHERE clauses should some day function as ANDs, and ditto HAVINGs, which is another reason not to reuse HAVING for this: just to leave that a possibility, remote though it might be. My advice is to wait till QUALIFY is standardized, then hold your nose and adopt it, or maybe sooner when it becomes clear that it will be standardized (because so many other RDBMSes have it too).
