I am trying to get a sum of column values in a Google Spreadsheet only if there is no value in the adjacent column. Consider the following example:
A | B
----------
40 | 50
20 | 20
30 |
10 |
The sum of A should return 40.
I tried to use the following function:
=SUM(FILTER(A:A, ISEMPTY(B:B) ))
but all I get is: Error: Unknown function name ISEMPTY. Can anyone tell me whats wrong or how to do it properly?
Thank you.