Week over Week Comparison

phanimusunuri9

You should have Year, Week Number and Weekday columns in your table. Or you can generate with calculated column. 

WeekNumber = WEEKNUM(Table[Date],2)

WeekDay = WEEKDAY(Table[Date],2)

Then you can create a measure like: 

Difference =
SUM ( Table[Sales] )
    - CALCULATE (
        SUM ( Table[Sales] ),
        FILTER (
            ALL ( Table ),
            Table[Year] = MAX ( Table[Year] )
                && Table[WeekNumber]
                    = MAX ( Table[WeekNumber] ) - 1
                && Table[WeekDay] = MAX ( Table[WeekDay] )
        )
    )

Regards,