求教SQL语句.速来,多谢

求教SQL语句............................................................速来,谢谢
有数据表如下：
   id                    cont
A0001                3
A0002                2
A0003                5

欲得到如下结果：
  id                   num
A0001                 1
A0001                 2
A0001                 3
A0002                 1
A0002                 2
A0003                 1
A0003                 2
A0003                 3
A0003                 4
A0003                 5
------解决思路----------------------
SELECT T1.ID, T2.NUM
  FROM 表 T1,
       (SELECT ROWNUM NUM
          FROM DUAL
        CONNECT BY ROWNUM <= (SELECT MAX(CONT) FROM 表)) T2
 WHERE T1.CONT >= T2.NUM