--通过父节点查询子节点
WITH
TREE AS(
SELECT * FROM Role
WHERE RoleID = 4 -- 要查询的父 id
UNION ALL
SELECT Role.* FROM Role, TREE
WHERE Role.ParentRoleID = TREE.RoleID
)
SELECT * FROM TREE
原文：http://www.cnblogs.com/wln3344/p/4252486.html