I've been using the following formula from the xldynamic website detailing
sumproduct usage as a base for retrieving uniqe instances in a data series.
I've been trying to modify the formula to allow me to utilize one additional
criteria.
Original formula:
=SUMPRODUCT((A1:A20<"")/COUNTIF(A1:A20,A1:A20&""))

Here is my formula:
=SUMPRODUCT((($O$7:$O$2710<"")*($M$7:$M$2710="198 6"))/COUNTIF($O$7:$O$2710,$O$7:$O$2710&""))

I'm trying to say how many unique instances are there for column O, where
column m = "1986?" Not sure what I'm doing wrong but help would be
appreciated.

tia,
Dave


This seems to apply only the second criteria