oracle如何把一行数据拆分成多行数据

表如下
a        b          c
A      1000     4

要拆成
a       b         c
A    1000     1
A    1000     2
A    1000     3
A    1000     4

with t as
 (select 'A' a, 1000 b, 4 c from dual)
select a,b,level c
  from t
connect by a = prior a
       and level <= c
       and prior dbms_random.value is not null