[JP Ronse]

Hi All,

I would like to count a sort of diversity per person and per month.

Sample data:

Customer Engineer Date
A JP 01/11/2009
A Bill 01/11/2009
A Bill 01/11/2009
A JP 01/11/2009
B JP 01/11/2009
A JP 01/12/2009
B Bill 01/12/2009
C Bill 01/12/2009
D Bill 01/12/2009
E Bill 01/12/2009


In November, JP has served customers A & B, Bill only for A. The result for
JP is 2 while for Bill, it is 1.

In December: JP=1, Bill = 4.

With {=COUNTDIFF((A2:A11)&(B2:B11))} I am already able to calculate over the
whole range the differing combinations, but how to include the criteria
person and month? Any help will be very appreciated.

With kind regards,

JP