使用connect by... start with...子句就可以方便地进行hierarchical查询,示例:
select empno, ename, mgr
from emp
connect by prior empno = mgr
start with empno = 1;
select empno, ename, mgr
from emp
connect by prior empno = mgr
start with empno = 1;
用connect by... start with...就可以了start with...要跟着你的起始值.