Calculating Last 3 Month Production

[Buzz1126]

I need to calculate the Last 3 Months of Production using Dax.  I feel like the code below should be correct, but is missing something simple.  Can I use the word month, when using FiscalMonth Sales?  Are there any other metrics needed?  I also have access  to a Calendar Table which could work.

I attempted a solution but am getting a syntax error.  

3 month = CALCULATE(
	SUM(FactProductionTransactionDetail[Quantity]),
	DATESINPERIOD(DimDate[FiscalMonthNumber],DimDate[FiscalMonthNumber] = "201912",-3,month))

[Buzz1126]

I attempted a new solution using Calendarmonth instead of FiscalMonth, but got the same result.  The other thing I forgot to mention is that I want it to calculate using the selected period instead of an entered period.  For instance, instead of typing "6" below, I want it to calculate previous 3 months sales based on a filter or a month column if the view is in a table.

3 month = CALCULATE(
	SUM(FactProductionTransactionDetail[Quantity]),
	DATESINPERIOD(DimDate[CalendarMonthNumber],DimDate[CalendarMonthNumber] = "6",-3,month))

[v-yuta-msft]

@Buzz1126 ,

Please modify the measure using dax below and check if it can meet your requirement:

3 month =
CALCULATE (
    SUM ( FactProductionTransactionDetail[Quantity] ),
    DATESINPERIOD (
        DimDate[CalendarMonthNumber],
        DimDate[CalendarMonthNumber] = SELECTEDVALUE ( Table[Selection] ),
        -3,
        MONTH
    )
)

Community Support Team _ Jimmy Tao

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Buzz1126]

Can you  use SELECTEDVALUE in an Analysis Services connection?