On Thu, 28 Aug 2008 21:06:01 -0700, JLatham <HelpFrom @
Jlathamsite.com.(removethis) wrote:

That's always a good thing to think of. Another thing, especially if lots of
dates or comparisons are going to take place, is speed. SUMPRODUCT() is a
pretty slow operation, and so the formula I put up earlier might offer better
performance IF there are lots of comparisons to be made. But for relatively
few comparisons, you would probably be hard pressed to measure any difference
in how long it took to get the results.
I personally prefer the SUMPRODUCT() solution over the brute force one I put
up simply because it is easier to understand and maintain. Most people get
confused to some degree when dealing with lots of logic statements (OR/AND)
in formulas, so that makes them more difficult to manage and maintain in the
long run.


No question that understandability and ease of maintenance are important
considerations. I sure have stuff I've done that works fine, but, in trying to
change/extend it, it takes me quite a while to figure out what I did!
--ron