SQL Debet, Kredit, Saldo

mysql> select @s:=0
+-------+
| @s:=0 |
+-------+
|     0 |
+-------+
1 row in set (0.00 sec)
 
mysql> select @k:=if(kode="k",nominal,0) as Kredit,@d:=if(kode="d",nominal,0) as
 debet, @s:=@s+@k-@d as saldo from trx
+--------+-------+-------+
| Kredit | debet | saldo |
+--------+-------+-------+
|   3434 |     0 |  3434 |
|   3434 |     0 |  6868 |
|   4434 |     0 | 11302 |
|      0 |   544 | 10758 |
|      0 |   453 | 10305 |
+--------+-------+-------+
5 rows in set (0.00 sec)