Calculate prior month sales without a Date table

Prior_Month_Sales.dax

Revenue PM = 
var prior_month_start_date = EOMONTH( MIN ( Sales[Date] ), -2 ) + 1
var prior_month_end_date = EOMONTH( MIN ( Sales[Date] ), -1 ) + 1
RETURN
CALCULATE( 
    SUM ( Sales[Revenue] ), 
    FILTER ( 
        ALLSELECTED ( Sales ), 
        Sales[Date] >= prior_month_start_date  && Sales[Date] < prior_month_end_date 
    )  
)