I have a requirement that I need to create a Column by adding the Previous Row data to the current row to get the value. 

This is for a SQL Query Table.

For Eg: 

Column Name: " Revenue Difference"

Row 1: April 2017:: (Budgeted Revenue Row 1 - Actual Revenue Row 1) = "Revenue Difference - Row 1"

Row 2: August 2017 :: "Revenue Difference - Row 1" + ((Budgeted Revenue Row 2 - Actual Revenue Row 2) = "Revenue Difference - Row 2"

Row 3: June 2017 :: "Revenue Difference - Row 2" + ((Budgeted Revenue Row 3 - Actual Revenue Row 3) = "Revenue Difference - Row 3"

Row 4: May 2017 :: "Revenue Difference - Row 3" + ((Budgeted Revenue Row 4 - Actual Revenue Row 4) = "Revenue Difference - Row 4"

I have attached the snapshot for better understanding.

Can you please give me the SQL Code that I can add to this Query Table to get the above functionality?

Best,

Vikram