Hello.

I need to count unique values in a list. I have many ways to do this (I am
currently using an array function {=SUM(IF(COUNTIF(A9:A1000,A9:A1000)=0, 0,
1/COUNTIF(A9:A1000,A9:A1000)))}, and that works fine.

But - I wish to be able to filter the list and have the function adjust to
only the visible cells.

I tried substituting the SUBTOTAL function for SUM in the formula above, but
I get an ERROR result.

I am willing to use intermediate columns if I must. Can anyone help?