oracle 行转列

SQL> desc a;
 名称                                      是否为空? 类型
 ----------------------------------------- -------- ------------------------

 AID                                                NUMBER(10)
 NAME                                               CHAR(1)


SQL> select * from a;

       AID N
---------- -
         1 a
         1 b
         1 c
         2 d
         2 e
         2 f

select aid,wmsys.wm_concat(name) name from a group by aid;