Dynamically calculate Count of Rows for a specific Year/Month

Hi, fellin 

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

Table:

Calendar(a calcualted table):

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

You may create three measures as below.

Count Start = 
var ym = MAX('Calendar'[YearMonth])
return
COALESCE(
    COUNTROWS(
        FILTER(
            ALLSELECTED('Table'),
            (YEAR([Start Date])*100+MONTH([Start Date]))=ym
        )
    ),0
)

Count End = 
var ym = MAX('Calendar'[YearMonth])
return
COALESCE(
    COUNTROWS(
        FILTER(
            ALLSELECTED('Table'),
            (YEAR([End Date])*100+MONTH([End Date]))=ym
        )
    ),0
)

Count Open = 
var x = MAX('Calendar'[YearMonth])
var tab = 
ADDCOLUMNS(
    ALLSELECTED('Table'),
    "Flag",
    var t = 
    SELECTCOLUMNS( 
        ADDCOLUMNS(
            CALENDAR(
                [Start Date],
                [End Date]
            ),
            "ym",
            YEAR([Date])*100+MONTH([Date])
        ),
        "ym",[ym]
    )
    return 
    IF(
       x in t,
       1,0
    )
)
return
COALESCE(
    COUNTROWS(
        FILTER(
            tab,
            [Flag]=1
        )
    ),
    0
)

Result:

Best Regards

Allan

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