declare @i int
set @i=1
while @i<=3
begin
.......//你的统计语句
end

------解决方案--------------------
SQL code

忘了累加了
declare @i int
set @i=1
while @i<=3--3表示你的月份
begin
.......--你的统计语句

set @i=@i+1
end

------解决方案--------------------

SQL code
--> 测试数据: #
if object_id('tempdb.dbo.#') is not null drop table #
create table # (f27 int,f28 int,f8 int,dw varchar(1),tbsj datetime)
insert into #
select 2,1,1,'A','2007-01-01' union all
select 2,1,1,'B','2007-01-01' union all
select 2,1,1,'A','2007-02-01' union all
select 2,1,1,'B','2007-02-01' union all
select 2,1,1,'A','2008-01-01' union all
select 2,1,1,'B','2008-01-01' union all
select 2,1,1,'A','2008-02-01' union all
select 2,1,1,'B','2008-02-01'

declare @tbsj datetime
set @tbsj = '20080301'

select
    dw=isnull(a.dw,b.dw),
    f27本年=a.f27,
    f28本年=a.f28,
    f8本年=a.f8,
    f27上年=b.f27,
    f28上年=b.f28,
    f8上年=b.f8
from
    (
        select dw,sum(f27)f27,sum(f28)f28,sum(f8)f8 from #
        where year(tbsj)=year(@tbsj) and month(tbsj)<=month(@tbsj)
        group by dw
    ) a
full join
    (
        select dw,sum(f27)f27,sum(f28)f28,sum(f8)f8 from #
        where year(tbsj)=year(@tbsj)-1 and month(tbsj)<=month(@tbsj)
        group by dw
    ) b
on a.dw=b.dw

/*
dw   f27本年       f28本年       f8本年        f27上年       f28上年       f8上年
---- ----------- ----------- ----------- ----------- ----------- -----------
A    4           2           2           4           2           2
B    4           2           2           4           2           2
*/