Hi, I was wondering whether you could help me creating this formula because it's driving me mad.

I have a file, with the following fields: Brand, Media, Period (MMM-yy) and Investment. What I am trying to do is to generate an formula (in a Content block) so It does the following: total amount of investment in Open TV in brand of the selected period ABOVE total amount of investment in Open TV of the selected period.

I want it to change according to what I select in the right sidebar. I am trying to create the formula in the Content View, but it keeps on colouring my parameters in red, as if they are wrong.

How do you suggest I should do this?

Thanks in advance for your help.