Hopefully I explain this well.I have a sheet with 2 tabs, Data and Report. I am trying to make a formula on the Report tab that sums up total paid by new Clients.
Essentially: Look at Data!A:I, find all Clients who appear in December 2021 (aka F3) but not November 2021 (aka E3) and sum up their Column I. In the case of the above example, it'd pop out $2, the sum of I6 and I7 - since Clients C and D are new.