数据库中如何使用SQL查询连续号码段

(第二个字段内可能是连续的数据，可能存在断点。)

怎样能查询出来这样的结果,查询出连续的记录来。
就像下面的这样？
2014,00000001,00000005
2014,00000009,00000007
2013,00000120,00000122
2013,00000124,00000125 

SQL> SELECT b.fphm, MIN (b.kshm) Start_HM, MAX (b.kshm) End_HM
2 FROM (SELECT a.*, TO_NUMBER (a.kshm - ROWNUM) cc
3 FROM (SELECT *
4 FROM t
5 ORDER BY fphm, kshm) a) b
6 GROUP BY b.fphm, b.cc
7 /

FPHM START_HM END_HM
---------- -------- --------
2013 00000120 00000122
2013 00000124 00000125
2014 00000001 00000005
2014 00000007 00000009