It is not trying to be an example for different ranges, but for the same
range. Therefore as it cannot be both conditions there is no need to avoid
duplicate counting. At this point it is just introducing OR, to add the
further complication of duplications would be too soon IMO. And SIGN is not
the only way to test for duplicates, so it doesn't have to be SIGN.

--
__________________________________
HTH

Bob

"Bernd P" wrote in message
...
Hello Bob,

Hmm, the OR example is ok now but still a little bit misleading
because you can't just add the criteria comparisons for overlapping
criteria. Their sum has to get SIGN()'ed to make it a foolproof OR (or
you might end up double counting overlaps).

Regards,
Bernd