SQL> select * from tree;BH         MC                   SJBH
---------- -------------------- ----------
1          china
2          ShangHai             1
3          ShangHai-1           2
4          BeiJin               1
5          ShangHai-2           2SQL> select * from tree
  2  start with bh='2'
  3  connect by prior bh=sjbh;BH         MC                   SJBH
---------- -------------------- ----------
2          ShangHai             1
3          ShangHai-1           2
5          ShangHai-2           2