How to create Dax logic for this Month and Previous Month

Hi Chaitanya122 ,

I created a sample pbix file(see attachment) for you, please check whether that is what you want. You can create a measure as below:

Measure = 
VAR _selyear =
    SELECTEDVALUE ( 'Date'[Year] )
VAR _selmonth =
    SELECTEDVALUE ( 'Date'[Month] )
VAR _selym =
    SELECTEDVALUE ( 'Date'[YearMonth] )
VAR _amount =
    CALCULATE (
        SUM ( 'Table'[Amount] ),
        FILTER (
            'Table',
            YEAR ( 'Table'[Date] ) = _selyear
                && FORMAT ( 'Table'[Date], "mmmm" ) = _selmonth
        )
    )
VAR _predate =
    CALCULATE (
        MAX ( 'Table'[Date] ),
        FILTER (
            ALLSELECTED ( 'Table' ),
            VALUE ( YEAR ( 'Table'[Date] ) & FORMAT ( 'Table'[Date], "mm" ) )
                < VALUE ( _selym )
        )
    )
VAR _preamount =
    CALCULATE (
        SUM ( 'Table'[Amount] ),
        FILTER (
            ALLSELECTED ( 'Table' ),
            YEAR ( 'Table'[Date] ) = YEAR ( _predate )
                && MONTH ( 'Table'[Date] ) = MONTH ( _predate )
        ),
        ALL ( 'Date' )
    )
RETURN
    IF ( ISBLANK ( _amount ), _preamount, _amount )

In addition, you can refer the following blog to get it.

Power BI DAX Getting the Value of Previous Non-NULL Row

If the above one can't help you get the desired result, please provide some sample data in your tables (exclude sensitive data) with Text format and your expected result with backend logic and special examples. It is better if you can share a simplified pbix file. Thank you.

How to upload PBI in Community

Best Regards