difference from previous row in a measure

Hi RENJITH_R_S 
You can achieve your goal, using the offset function.

1. Create a basic sum measure:

SumValue = sum('Table'[Value])

2. Use it on your offset calculation measure:

ValuesDiff = [SumValue]-

CALCULATE([SumValue],OFFSET(-1,ALLSELECTED('Table'[Period]),ORDERBY('Table'[Period],ASC)))

Link to a Sample file 

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if you use a slicer or you have spaces in the date, it's better to write the measure like this

CALCULATE(
      [SumValue],
       OFFSET(-1,
            SUMMARIZE(ALLSELECTED('Table'),'Table'[Period]),ORDERBY('Table'[Period],ASC)))