Substract a month

hi...  its there any posibility to Substract 1 month to a selected month.

i need to show just 3 column of month... a month to select (maybe with @Promp) and month -1, and month -2.

for ex. "select March. besides in a left column the month -1  (February) and in another column the month -2 (Jannuary) with their sales.

trying to use a Filter on Month ("March")... but dont show february or jannuary values.

trying to use "Month -1" but it says its not a valid type of data. (Máx(Month)-1...  etc etc...  didnt work)

trying to build 3 query with month (@promp), month-1, and month-2 and seems to work well... the problem with that is i have to do this 18 times )

Thanks !!