Running Sum in Power BI for Ticket Backlog - Advanced

Hi Anonymous ,

You can try to use following measure formulas if it works: 

cCreated = 
CALCULATE (
    COUNT ( data[ID] ),
    FILTER (
        ALLSELECTED ( data ),
        FORMAT ( [Created], "mm/yyyy" ) = FORMAT ( min ( 'Table'[Date] ), "mm/yyyy" )&&[Created]<>BLANK()
    )
)

cResolved = 
CALCULATE (
    COUNT ( data[ID] ),
    FILTER (
        ALLSELECTED ( data ),
        FORMAT ( [Resolved], "mm/yyyy" ) = FORMAT ( min ( 'Table'[Date] ), "mm/yyyy" )&&[Resolved]<>BLANK()
    )
)

cUnsolved = [cCreated]-[cResolved]

BackLog = 
VAR currDate =
    MIN ( 'Table'[Date] )
VAR prev =
    SUMX (
        SUMMARIZE (
            FILTER ( ALL ( data ), [Created] < currDate ),
            [Created].[Year],
            data[Created].[Month],
            "Count", COUNT ( data[ID] )
        ),
        [Count]
    )
        - SUMX (
            SUMMARIZE (
                FILTER ( ALL ( data ), [Resolved] < currDate ),
                [Resolved].[Year],
                [Resolved].[Month],
                "Count", COUNT ( data[ID] )
            ),
            [Count]
        )
RETURN
    prev + [cUnsolved]

Regards,

Xiaoxin Sheng