帮忙看是为什么?
create   table   a(kaiyongshijian     datetime   ,           shedingshijian     int   ,ID     int   ,     beizhu   varchar(100))
insert   into   a
select   '2007-4-3   12:00:00 ',12,1, ' '     union   all
select   '2007-4-3   12:00:00 ',15,5, ' '   union   all
select   '2007-4-3   12:00:00 ',20,9, ' '   union   all
select   '2007-5-3   12:00:00 ',10,2, ' '   union   all
select   '2007-5-3   12:00:00 ',7,3, ' '   union   all
select   '2007-5-3   12:00:00 ',5,6, ' '  


declare   @n   int,   @year   int
set   @year   =2008                         --設置年份
set   @n=0
while   @@rowcount> 0
begin
    set   @n=@n+1
    insert   into   b
      select   dateadd(month,shedingshijian*@n,   kaiyongshijian   ),ID,beizhu
      from   a
    where     year(dateadd(month,shedingshijian*@n,   kaiyongshijian)   )=@year
end
为什么只能算出来2008年的?别的年份都算不出

------解决方案--------------------
這麼用倒是可以

create table a(kaiyongshijian datetime , shedingshijian int ,ID int , beizhu varchar(100))
insert into a
select '2007-4-3 12:00:00 ',12,1, ' ' union all
select '2007-4-3 12:00:00 ',15,5, ' ' union all
select '2007-4-3 12:00:00 ',20,9, ' ' union all
select '2007-5-3 12:00:00 ',10,2, ' ' union all
select '2007-5-3 12:00:00 ',7,3, ' ' union all
select '2007-5-3 12:00:00 ',5,6, ' '

create table b(kaiyongshijian datetime , ID int , beizhu varchar(100))

declare @n int, @year int
set @year =2009 --設置年份
set @n=0
--while @@rowcount> 0
while @n <= 100
begin
set @n=@n+1
insert into b
select dateadd(month,shedingshijian*@n, kaiyongshijian ),ID,beizhu
from a
where year(dateadd(month,shedingshijian*@n, kaiyongshijian) )=@year
end

Select * From b

Drop Table a,b