Context: We are looking at the First Half of Feb (Feb 1-14).
Goal: Compare it to the previous month.
Ready...
💻 DAX Formula
-- Scenario 1: Exact Match (Jan 1-14)
MEASURE PrevMonth_Strict =
CALCULATE( SUM(Sales[Amt]), DATEADD(Dates, -1, MONTH) )
-- Scenario 2: Full Period (Jan 1-31)
MEASURE PrevMonth_Full =
CALCULATE( SUM(Sales[Amt]),
PARALLELPERIOD( Dates, -1, MONTH )
) -- Ignores that we selected only half of Feb