Rolling 12 months by grouping it 12 times and calculate 12 months = sum(m2)/avg(m1)
I have a report that has rolling 12 months = sum(m2)/avg(m1) using current month as Nov. 2021 and it happens 12 times preceding the next previous month until we are at previous month Dec. 2019 to previous 12 months Nov. 2020
So I need, for a month, the average for the previous 12months. And I need that for a rolling 12 period but not having much luck. Does anyone have an input?