在SqlServer中通过SQL语句实现树状查询

 CREATE PROCEDURE [dbo].[GetTree]
 @Id int
 AS
 BEGIN
     with cte as
     (
         select Id,Pid,Name,0 as lvl from Entity
         where Id = @Id
         union all
         select e.Id,e.Pid,e.Name,lvl+1 from cte c inner join Entity e
         on c.Id = e.Pid
     )
     select * from cte
 END