Counting Null

[caiogil1]

Hello everyone,

The task looks easy but I am stuck on this, so anyone know how to count null like in the image

I wanna count all the null cells in that table on the right, this means every day that there is no sale(measure field = qty_sold)

Just explaining a bit more
I have an master calendar (day,month,year...) creating every day from the min(date) to max(date)

This formula gets all the day that are not null but I wanna just the opposite

Count({$<QTD_VDA_UND-={"=Null()"}>}distinct DTA_AGENDA)

someone to help??

[#2]

Count({$<QTD_VDA_UND-={""}>}distinct DTA_AGENDA)