sql 基础 5 树查询

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select * from
(select t.postid,
        t.name,
        t.parentid
from gaus_postinfo t
start with t.parentid ='GAUS_POSTINFO_8e29081b-8cba-41be-a1da-fdba0ba94a86' 
connect by prior t.postid = t.parentid 
)treeTable


--查看树
select * from
(select a.menu_name,
       a.parent_id,
       level "层次",
       sys_connect_by_path(menu_name, '.') "合并层次",
       prior a.menu_name "父节点",
       connect_by_root a.menu_id "根节点",
       decode(connect_by_isleaf, 1, a.menu_name, null) "子节点",
       decode(connect_by_isleaf, 1, '是', '否') isleaf
from ipbp_webmenu a
start with a.parent_id =1003 --从parent为空开始扫描
connect by prior a.menu_id = a.parent_id --以child为父列连接parent
order siblings by menu_id desc --对层次排序
)treeTable
where treeTable.isleaf='是'