DSXchange

Hello Everybody,

I have a requirement to generate previous row value where first record should populate null .

Input :

Emp_ID salary

100 1000

200 1500

300 2000


Output:

Emp_ID salary Previous_Salary

100 1000 NULL

200 1500 1000

300 2000 1500


I guess this can be performed by writing staging variables to compare the rows .

Please somebody provide me the logic to generate the stage variables

Thanks

Doesn't Search work for you? This technique has been described on a number of occasions.

In your case you need two stage variables. Let's call them svNewPreviousSalary, which will become the value of the Previous_Salary output column, and svPreviousSalary, which will be used to "remember" the previous salary. Each is initialized to SetNull().
Derivations are as follows. When svNewPreviousSalary is being evaluated, svPreviousSalary still contains the value from the previous row.

Thank you ray for the logic..It worked for me.

Here is my output from the stagevariables based on the following order :
EID Salary svNewPreviousSalary svPreviousSalary

100 1000 null 1000

200 1500 1000 1500

300 2000 1500 2000

Thanks