Set analysis from the same field

[#1]

Hi,

I'm trying to set something on a table chart that uses an equation that pulls from a previous month/year id:

      =(sum({$<SNAPSHOT_MONTH_ID = {SNAPSHOT_MONTH_ID}-1>}, MembershipFlag))/(sum(MembershipFlag))

I want to divide that 2nd snapshot_month_id by the first one. I think my set analysis is wrong though. I simply want to subtract 1 from the current month ID. Is there a way to do this?

Thanks,

Joe

[#2]

Thanks, the above function worked like a charm.

Joe