How to I sum one column ONLY when another column is NOT NULL

[KellyMc]

I have a table with month, category, ACTUAL Revenue, and PROJECTED Revenue as variables. The Actual revenues are populated only for year-to-date (by month) so when I sum them, I get the Actual YTD revenue. 

I want to calculate the YTD Projected Revenue by counting ONLY the monthly projected revenue values where the matching Actual Revenue value is NOT NULL.

I tried doing this multiple times and thought the following expression would work, but it's returning zero.

=sum({<Actual={'>0'}>} Projection)

[tresesco · Accepted solution]

Try like:

=sum({<Actual={">0"}>} Projection)                     // double quotes for greater than zero

Or,

=sum({<Actual={"*"}>} Projection)                       // for not null