Identifying unique values among duplicates

[bob]

If sheet2 cols A and C match the value in sheet1 cols H and I, I want to
return the number of unique values in sheet 1 column A. Can anyone provide a
formula for accomplishing this:

The following example should yield a result of 2 for the Arenas/Bibby
combination because there are two rows in sheet1 where Arenas is in colH and
Bibby in colI, AND the date in colA is unique (10/29/08 and 10/30/08):

sheet2
colA colC
Arenas Bibby


sheet1
colA colH colI
10/29/08 Butler Simmons
10/29/08 Arenas Bibby
10/29/08 Thomas Brown
10/30/08 Arenas Bibby
10/30/08 Stevens Hale
10/30/08 Arenas Bibby
10/30/08 Stevens Simmons
10/31/08 Arenas Simmons


Thanks,
Bob

 

[T. Valko]

Try this array formula** entered on Sheet1:

=COUNT(1/FREQUENCY(IF((H2:H9=Sheet2!A1)*(I2:I9=Sheet2!C1),A2:A9),A2:A9))

** array formulas need to be entered using the key combination of
CTRL,SHIFT,ENTER (not just ENTER)

 

[bob]

Biff,

This works very well and yields the correct answer when I set up the formula
in sheet1, but how would I set up the formula in sheet2 (which is where I
really want it)?

Bob

 

[bob]

Never mind. I figured out how to do it. Thanks for your help.

Bob

 

[T. Valko]

Good deal. Thanks for the feedback!