转换组合函数wm_concat

Oracle10g以上的版本中提供了转换组合函数。
例如表test_t的原始数据查询结果为:

select * from latty.test_t
1	200405	5761	G	7393344.04
2	200405	5761	J	5667089.85
3	200405	5762	G	6315075.96
4	200405	5762	J	6328716.15
5	200405	5763	G	7393344.04
6	200405	5763	J	5667089.85
7	200405	5764	G	6028670.45
8	200405	5764	J	6459121.49
9	200405	5765	G	13156065.77
10	200405	5765	J	11901671.70
11	200406	5761	G	7614587.96
12	200406	5761	J	5704343.05
13	200406	5762	G	6556992.60
14	200406	5762	J	6238068.05
15	200406	5763	G	7614587.96
16	200406	5763	J	5704343.05
17	200406	5764	G	6387706.01
18	200406	5764	J	6907481.66
19	200406	5765	G	13562968.81
20	200406	5765	J	12495492.50
21	200407	5761	G	7987050.65
22	200407	5761	J	5723215.28
23	200407	5762	G	6833096.68
24	200407	5762	J	6391201.44
25	200407	5763	G	7987050.65
26	200407	5763	J	5723215.28
27	200407	5764	G	6456433.23
28	200407	5764	J	6987660.53
29	200407	5765	G	14000101.20
30	200407	5765	J	12301780.20
31	200408	5761	G	8085170.84
32	200408	5761	J	6050611.37
33	200408	5762	G	6854584.22
34	200408	5762	J	6521884.50
35	200408	5763	G	8085170.84
36	200408	5763	J	6050611.37
37	200408	5764	G	6587559.23

比如现在查看这条SQL:
 

 select wm_concat(area_code) 用户名  from latty.test_t group by bill_month;

执行结果为:

1	5761,5761,5762,5763,5764,5765,5765,5764,5763,5762
2	5761,5762,5763,5764,5765,5765,5764,5763,5762,5761
3	5761,5764,5765,5765,5764,5763,5761,5762,5763,5762
4	5761,5762,5762,5763,5764,5763,5761