Getting Cumulative Sum

Consider the following employees data as source

employee_id, salary
10, 1000
20, 2000
30, 3000
40, 5000

Design a mapping to load the cumulative sum of salaries of employees into target table?
The target table data should look like as

employee_id, salary, cumulative_sum
10, 1000, 1000
20, 2000, 3000
30, 3000, 6000
40, 5000, 11000

Solution:

Follow these steps,

You need to give below conditions in expression transformation,