How to create debit / credit & Balance query in SQL

Question

I need expected output

id          RefNo      TransDate  Dr                    Cr		Balance
----------- ---------- ---------- --------------------- ---------------------
            Opning balance						40
3           003        2013-01-03 300.00                0.00		340
4           004        2013-01-04 0.00                  100.00		240
5           004        2013-01-05 200.00                0.00		440

Best Regards 

Sanjeev