在SqlServer中通过SQL语句实现树状查询

 1 CREATE PROCEDURE [dbo].[GetTree]
 2 @Id int
 3 AS
 4 BEGIN
 5     with cte as
 6     (
 7         select Id,Pid,Name,0 as lvl from Entity
 8         where Id = @Id
 9         union all
10         select e.Id,e.Pid,e.Name,lvl+1 from cte c inner join Entity e
11         on c.Id = e.Pid
12     )
13     select * from cte
14 END