=if( sum({<[MonthYear],Date={">=$(=MonthStart(AddMonths(Max(Date),-3)))<=$(=MonthEnd(AddMonths(Max(Date),-1)))"}>} [Sales])=0 and sum({$<[MonthYear],[Year]={"$(=Year(Max(Date)))"},[Month]={"$(=Month(Max(Date)))"} >}[Sales])>0 and [RegistrationDate]<monthstart(addmonths(max(Date),-3)) ,1,0)
This is a flag showing a customer reactivated after 3 months of no sales.
I would like to SUM how many clients have I reactivated per month in simple table:
