you can remove your filter and replace your calculation with
if ZN(SUM([Sales])) - LOOKUP(ZN(SUM([Sales])), -1) < 0 then ZN(SUM([Sales])) - LOOKUP(ZN(SUM([Sales])), -1) end
So , if negative show the value otherwise show null. See in the attached
Incredibly simple which I love, but still doesn't give me the results that I'm looking for. I'm guessing I didn't explain it well.
I want to see the total sales for all months for all the sub-categories that have a negative month to month difference, but I don't want to see the subcategories that always have a positive result. In my real set of data I'm using over 300 rows so scrolling down doesn't really work well.
While this removes the value of the difference, it is still showing all the subcategories like "Appliances" which is always increasing. Ideally, "Appliances" wouldn't even be visible in the returned results. Chairs, Fasteners, Paper, and Supplies are also like this. When it is a small data set like the example, this would work, but not when it is a large data set.
Hope that helps clarify.
That's exactly what I'm looking for! Many thanks!