oracle的 start with XXX connect by prior的用法、遍历查询父节点和字节点

select … from tablename
start with 条件1
connect by 条件2
where 条件3;

#实例


##查询某节点和其子节点
select * from tablename
start with parentid='XXX'
connect by parentid==childid

##查询某节点和其父节点
select * from tablename
start with childid='XXX'
connect by childid==parentid

start with 子句：遍历起始条件，有个小技巧，如果要查父结点，这里可以用子结点的列，反之亦然。connect by 子句：连接条件。