connect by prior id= pid start with id='1' 树结构查询

基础表创建：

with temp as (
select '公司' name, '' id, '' pid from dual union all
select '部门1'  name , '' id, '' pid from dual union all
select '部门2'  name , '' id, '' pid from dual union all
select '员工11' name , '' id , '' pid from dual union all
select '员工12' name , '' id , '' pid from dual union all
select '员工21' name , '' id , '' pid from dual
)

等号左边的字段为基础，查询右边字段=左边字段的

level可以查看距离父节点的距离

从上往下查

通过根节点可以获取包括该根节点及以下的所有子节点

select temp.*,level from temp
connect by prior id= pid
start with id=''

根节点可以多选

select * from temp
connect by prior  id= pid
start with id in ('' ,'')

添加where语句

select * from temp
where id = ''
connect by prior  id= pid
start with id in ('' ,'')

从下往上查

select * from temp
connect by prior pid= id
start with id = ''