根据条件 求相邻的两条数据的某字段的差,该怎么解决

create table tmp
(
    id int null,
    [money] money null,
    state int null
)
insert into tmp 
select 1,22.2,0
union all select 5,20,0
union all select 6,35,0
union all select 7,30,1
union all select 8,50,1
union all select 12,30,0
union all select 16,20,1

create procedure substract
    @state int
as
begin
    select d.aid,c.amoney,c.sub  from
    (select c.aid,MIN(c.bid) as cbid from (
    select a.money as amoney,a.id as aid,b.id as bid,b.money-a.money as sub from 
    (select ID,[money],state from tmp where state=@state) a,
    (select ID,[money],state from tmp where state=@state) b) c
    where c.bid>c.aid
    group by c.aid) d,
    (select a.money as amoney,a.id as aid,b.id as bid,b.money-a.money as sub from 
    (select ID,[money],state from tmp where state=@state) a,
    (select ID,[money],state from tmp where state=@state) b) c
    where c.aid=d.aid and c.bid=d.cbid
end



--结果
select * from tmp where state=0
exec substract 0


id          money                 state
----------- --------------------- -----------
1           22.20                 0
5           20.00                 0
6           35.00                 0
12          30.00                 0

(4 行受影响)

aid         amoney                sub
----------- --------------------- ---------------------
1           22.20                 -2.20
5           20.00                 15.00
6           35.00                 -5.00

(3 行受影响)