数据库学习（1）：树查询

SELECT t.guid,
t.name,
t.icon,
t.parentguid
FROM test t
start with t.parentguid= '48D37AB8-EA5D-4D91-9CAA-A986F35891W4'
connect by t.parentguid=prior t.guid
ORDER SIBLINGS BY T.guid

WITH temp
AS
(
--父项
SELECT * FROM Flow_UserGroup WHERE ParentId is null
UNION ALL
--递归结果集中的下级
SELECT m.* FROM Flow_UserGroup AS m
INNER JOIN temp AS child ON m.ParentId = child.Id
)
SELECT * FROM temp