Hi all VFP users/experts

I have a table as follows of employees salary data

empl_no  WEF         Salary
0001     01/01/1998  2000
0001     01/01/1999  2500
0001     01/01/2000  3000
0001     01/02/2001  3200

How can I construct a SQL to generate follwing cursor

empl_no  WEF         New Salary     Old Salary
0001     01/01/1998  2000           NULL
0001     01/01/1999  2500           2000
0001     01/01/2000  3000           2500
0001     01/01/2001  3200           3000

Would appreciate all help. Thanks