Need help on MySQL query

Hi Experts, EID Mubarak to all. I need your help on writing a MySQL query. Scenario: CREATE TABLE transaction ( id int NOT NULL ATUTO INCREMENT, date datetime NOT NULL, withdrawn double (12,2) NULL, deposit double (12,2) NULL ); SELECT * FROM transaction; id date withdrawn deposit ----- ----------------------------- --------------- -------------- 1 2008-12-01 00:00:00 NULL 10000.00 2 2008-12-02 00:00:00 4000.00 NULL 3 2008-12-04 00:00:00 2000.00 NULL 4 2008-12-05 00:00:00 NULL 4500.00 5 2008-12-06 00:00:00 500.00 1500.00 The above is all I have. I want to make query which should output an extra calculated column named "balance", something like following: Expected output from query: id date withdrawn deposit balance ----- ----------------------------- --------------- -------------- ------------- 1 2008-12-01 00:00:00 NULL 10000.00 10000.00 2 2008-12-02 00:00:00 4000.00 NULL 6000.00 3 2008-12-04 00:00:00 2000.00 NULL 4000.00 4 2008-12-05 00:00:00 NULL 4500.00 8500.00 5 2008-12-06 00:00:00 500.00 1500.00 9500.00 Thanks in advance -- Rahat Bashir Dhaka, Bangladesh