last 12 months standard deviation on a table

Hi, Ortignano 

Based on your descirption, I created data to reproduce your scenario. The pbix file is attached in the end.

Tab:

Calendar(a calculated table):

Calendar = 
ADDCOLUMNS(
    CALENDARAUTO(),
    "YM",
    YEAR([Date])*100+MONTH([Date])
)

There is no relationship between two tables. You may create measures as below.

Sum Qty over last 12 Months = 
var ym = MAX(Tab[YearMonth])
return
CALCULATE(
    SUM(Tab[Qty]),
    FILTER(
        ALLEXCEPT(Tab,Tab[Product]),
        Tab[YearMonth] in 
        TOPN(
            12,
            CALCULATETABLE(
                DISTINCT('Calendar'[YM]),
                FILTER(
                    ALL('Calendar'),
                    [YM]<=ym
                )
            ),
            [YM]
        )
    )
)

STDEV Qty over last 12 Months = 
var ym = MAX(Tab[YearMonth])
return
CALCULATE(
    STDEV.P(Tab[Qty]),
    FILTER(
        ALLEXCEPT(Tab,Tab[Product]),
        Tab[YearMonth] in 
        TOPN(
            12,
            CALCULATETABLE(
                DISTINCT('Calendar'[YM]),
                FILTER(
                    ALL('Calendar'),
                    [YM]<=ym
                )
            ),
            [YM]
        )
    )
)

Result:

Best Regards

Allan

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