树的查询法
select * from t_role a 
START WITH a.parent_id='01'
CONNECT BY PRIOR a.role_id=a.parent_id 
这个查询怎么样才能把roleid是01的也查询出来呢

------解决方案--------------------

SQL code

select *
  from t_role a
 START WITH a.role_id = '01'  --改成role_id='01'试试
CONNECT BY PRIOR a.role_id = a.parent_id