Rolling average - How to cut the start point and end point of line

[ntdanh]

Dear Community,

Could you help me to adjust the DAX formula oF Rolling Avg 2Q yellow line to exclude the start point which is not enough data (2 quarter ) to calculate properly and the end point (2023Q2) as below ?

Rolling Avg 2Q = 
    VAR NumOfQuarters = 2
    VAR LastCurrentDate =
        MAX(DimDates[Date])
    VAR Period =
        DATESINPERIOD (DimDates[Date], LastCurrentDate, - NumOfQuarters, QUARTER )
    
    VAR Result = 
        CALCULATE (
           'Value/Qty Selection'[Value/Quantity]
            /2,
            Period
        )
   

RETURN
         Result

[Jihwan_Kim]

Hi,

I tried to create a sample pbix file like below.

Please check the below picture and the attached pbix file.

I hope the below can provide some ideas on how to create a solution for your  datamodel.

Qty total: = 
SUM( Sales[Quantity] )

Qty 2months rolling avg: =
VAR _currentrowquarterend =
    MAX ( 'Calendar'[End of Quarter] )
VAR _conditiontable =
    FILTER (
        ADDCOLUMNS (
            FILTER (
                ALL ( 'Calendar'[End of Quarter], 'Calendar'[Year-Quarter] ),
                'Calendar'[End of Quarter] <= _currentrowquarterend
            ),
            "qty", [Qty total:]
        ),
        [qty] <> BLANK ()
    )
VAR _condition =
    COUNTROWS ( _conditiontable ) >= 2
        && [Qty total:] <> BLANK ()
        && HASONEVALUE ( 'Calendar'[Year-Quarter] )
RETURN
    DIVIDE ( _condition, _condition )
        * CALCULATE (
            [Qty total:],
            WINDOW (
                -1,
                REL,
                0,
                REL,
                ALL ( 'Calendar'[End of Quarter], 'Calendar'[Year-Quarter] ),
                ORDERBY ( 'Calendar'[End of Quarter], ASC )
            )
        ) / 2