oracle start with connect by prior 递归查询

Oracle中的select语句可以用start with...connect by prior子句实现递归查询，connect by 是结构化查询中用到的，

其基本语法是：

select ... from <TableName>
where <Conditional-1>
start with <Conditional-2>
connect by <Conditional-3>;

<Conditional-1>：过滤条件，用于对返回的所有记录进行过滤;
<Conditional-2>：查询结果重起始根结点的限定条件;
<Conditional-3>：连接条件;

select dept_id ,dept_name,parent_id,stutas ,remark,
level as lev
from pub_depart_info
where  stutas=1
start with pub_depart_info.dept_id=''
connect by prior pub_depart_info.dept_id = pub_depart_info.parent_id
order by pub_depart_info.dept_id

其中：level为关键字，用于显示递归的层书