To Create a Variable which Subtracts the Current Row Value from Previous Row Value of teh same column, please follow the below steps.

1) Create a Variable “Previous_Value” and add $V{Current_Value} as the expression. This will Give a Invalid error as the Current_Value field is not created yet.


2) Create Current_Value Field and ass your column as expression.


3) Now Create the Difference Variable with subtract expression. (Here I will Create integer Variable and Convert My Prev and Curre Variable to integer.)


4) Now when we add the Diff Field into the report, the Report will display the difference from Currnet row value to the previous row value.