一个关于累加工资的TSQL语句

    今天在ITPUB看到一个人问的语句问题:http://www.itpub.net/thread-1734957-1-1.html

     问题如下:

table:emp
parent_id emp_id emp_name total_amout
NULL 2 Andrew 200
2 1 Nancy 100
2 3 Janet 120
3 4 Michael 80
1 5 Robert 50
每个员工的总销售额=自己的销售额+其下级员工的总销售额，
比如：
Andrew = 200_100_120_80_50=550
Nancy = 100+50=150
Janet = 120+80=200
Michael = 80
Robert = 50
这个用SQL怎样可以查询得到，请教一下大家???

    我用递归+游标实现了一下，总感觉应该有更好的实现方式，下面是我的实现方式:

WITH recur(parent_id , emp_id , emp_name , total_amout,tlevel)
 as
 (
    select parent_id , emp_id , emp_name , total_amout,0 as tlevel
    from emp as b
    where parent_id is NULL
    UNION all
    SELECT a.parent_id , a.emp_id , a.emp_name , a.total_amout,b.tlevel+1
    
    from emp as a INNER join recur b ON a.parent_id=b.emp_id
    
    
 )
 select * INTO emp_ext
 from recur
 
DECLARE @level int
 DECLARE @temp int
 select @level=max(tlevel) FROM emp_ext
 
while(@level>0)
 begin
     declare cursor_t cursor local static read_only forward_only
     for 
        select emp_id from emp_ext where tlevel=@level-1
         
        open cursor_t
         FETCH NEXT FROM cursor_t into @temp
         WHILE @@FETCH_STATUS=0
         BEGIN
         print @level
         update emp_ext set total_amout=(SELECT sum(total_amout) from emp_ext where parent_id=@temp)+(SELECT total_amout from emp_ext where emp_id=@temp)
         where emp_id=@temp
         FETCH NEXT FROM cursor_t into @temp
         END
         
        set @level=@level-1
         close cursor_t
         DEALLOCATE cursor_t
 end
 

   为了便于大家测试，我把生成表和数据的代码也复制如下:

CREATE table emp(
parent_id  int,
emp_id  int,
emp_name  varchar(50),
total_amout int
)

INSERT into emp(parent_id , emp_id , emp_name , total_amout)
VALUES (NULL   ,    2     ,  'Andrew'    , 200)
INSERT into emp(parent_id , emp_id , emp_name , total_amout)
VALUES (2     ,       1   ,    'Nancy',     100)
INSERT into emp(parent_id , emp_id , emp_name , total_amout)
VALUES (2     ,       3    ,   'Janet'  ,   120)
INSERT into emp(parent_id , emp_id , emp_name , total_amout)
VALUES (3     ,       4  ,     'Michael'  ,   80)
INSERT into emp(parent_id , emp_id , emp_name , total_amout)
VALUES (1       ,     5    ,   'Robert'   ,  50)

    大家谁有更好的实现办法，不妨在这讨论一下。