Get Previous Running Total for Missing Month

Hi, Anonymous 

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

ShipQty:

Date:

Date = CALENDAR(DATE(2001,1,1),DATE(2022,12,31))

There is a relationship between two tables.

You may create  calculated columns and a measure as below.

Calculated column:
YearMonth = VALUE(FORMAT('Date'[Date],"yyyymm"))
YearMonthDay = FORMAT('Date'[Date],"yyyy-mm-"&"01")
YearMonth2 = VALUE(FORMAT(ShipQty[Date],"yyyymm"))

Measure:
Result = 
CALCULATE(
    SUM(ShipQty[Qty]),
    FILTER(
        ALL(ShipQty),
        ShipQty[Item] = SELECTEDVALUE(ShipQty[Item])&&
        ShipQty[YearMonth2]<=SELECTEDVALUE('Date'[YearMonth])
    )
)

Result:

Best Regards

Allan

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