create table t(X int,  Y int,  Z varchar2(10));
insert into t values(1, 11, 'a');
insert into t values(1, 12, 'b');
insert into t values(1, 13, 'c');
insert into t values(1, 1211, 'g');
insert into t values(3, 31, 'e');
insert into t values(3, 32, 'f');


with t1 as (
select x, y, z, ','||wm_concat(y) over (partition by x)||',' y1 from t
)
select x, 
regexp_replace(regexp_replace(replace(y1, ','||y||',', ','), '^,',''), ',$', '') y,
z from t1;

---结果--
         X Y                    Z
---------- -------------------- ----------
         1 12,1211,13           a
         1 11,1211,13           b
         1 11,12,13             g
         1 11,12,1211           c
         3 31                   f
         3 32                   e

------解决方案--------------------

你妹的csdn 我的2楼哪里去了，里面有解决的sql，擦的。。。。。