非常典型的SQL，请高手赐教！

表A(促销活动开始日期:Start<date>,结束日期:End<date>,标志:Title<varchar>)，如何实现：根据当前日期判断，自动计算未来5天的状态？日期<Start时Title为'准促销'，日期>=Start时Title为‘促销’End的后一天Title为'回报日',End的第二天Title为'终止日',在此后面连续的日期则Title为'无效'。（提示:Start从当前实际日期开始，如存在End小于当前日期的不予考虑.）
情形一： Start='2011-06-09' End='2011-06-11' 时需实现：

  T+N： T+0[6.9] T+1[6.10] T+2[6.11] T+3[6.12] T+4[6.13] 
  Title: 促销 促销 促销 回报 终止

情形二: Start='2011-06-08' End='2011-06-10' 则需实现：
  
  T+N： T+0[6.9] T+1[6.10] T+2[6.11] T+3[6.12] T+4[6.13] 
  Title: 促销 促销 回报 终止 无效
 

情形三: Start='2011-06-10' End='2011-06-11' 则需实现：

  T+N： T+0[6.9] T+1[6.10] T+2[6.11] T+3[6.12] T+4[6.13] 
  Title: 准促销 促销 促销 回报 终止

  Start和End可同为空或同为不空，当同为空时，所有5天的Title都显示准促销，当不为空时(即为正常有效的日期区间时，则是上面需要实现的SQL。也就是说T+N是一定的，只是日期区间不同，Title显示不同而已.<好像就是这三种情况吧！如还有其它情况存在您可补充！> )

试试下面的,你可以更改系统日期看效果.
SQL code

create table tb(start datetime,[end] datetime,
title as (case when start>getdate() then '准促销'
        when start<=getdate() and [end]>=getdate() then '促销'
        when datediff(d,[end],getdate())<2 then '回报日'
        when datediff(d,[end],getdate())<3 then '终止日'
        when datediff(d,[end],getdate())>=3 then '无效'
end)
)
go
insert into tb(start,[end])
select '2011-06-09','2011-06-11' union all
select '2011-06-08','2011-06-10' union all
select '2011-06-10','2011-06-11'
go
select * from tb
/*
start                   end                     title
----------------------- ----------------------- ------
2011-06-09 00:00:00.000 2011-06-11 00:00:00.000 促销
2011-06-08 00:00:00.000 2011-06-10 00:00:00.000 促销
2011-06-10 00:00:00.000 2011-06-11 00:00:00.000 准促销

(3 行受影响)
*/
go
drop table tb

日期为空,则没法计算 5 天是从什么时候算起,因此似乎也应视为无效.

一:楼上（qianjin036a）貌似只显示了一天的啊，我用的 T=CASE WHEN，感觉太麻烦， 例如：Title =CASE WHEN start IS NULL THEN '准促销'... ，每个条件都要显示5天(5列)啊! 二.5天从当前实际日期算起。（如:今天:2011-06-09,所以上面的T+N,是从6.9开始算，明天6.10则为第一天.依此算）

要这样?
SQL code

create table tb(start datetime,[end] datetime)
insert into tb
select '2011-06-09','2011-06-11' union all
select '2011-06-08','2011-06-10' union all
select '2011-06-10','2011-06-11'
go
select *,
(case when start>getdate() then '准促销'
        when start<=getdate() and [end]>=getdate() then '促销'
        when datediff(d,[end],getdate())<2 then '回报日'
        when datediff(d,[end],getdate())<3 then '终止日'
        when datediff(d,[end],getdate())>=3 then '无效' end) as [T+0],
(case when start>dateadd(d,1,getdate()) then '准促销'
        when start<=dateadd(d,1,getdate()) and [end]>=dateadd(d,1,getdate()) then '促销'
        when datediff(d,[end],dateadd(d,1,getdate()))<2 then '回报日'
        when datediff(d,[end],dateadd(d,1,getdate()))<3 then '终止日'
        when datediff(d,[end],dateadd(d,1,getdate()))>=3 then '无效' end) as [T+1],
(case when start>dateadd(d,2,getdate()) then '准促销'
        when start<=dateadd(d,2,getdate()) and [end]>=dateadd(d,2,getdate()) then '促销'
        when datediff(d,[end],dateadd(d,2,getdate()))<2 then '回报日'
        when datediff(d,[end],dateadd(d,2,getdate()))<3 then '终止日'
        when datediff(d,[end],dateadd(d,2,getdate()))>=3 then '无效' end) as [T+2],
(case when start>dateadd(d,3,getdate()) then '准促销'
        when start<=dateadd(d,3,getdate()) and [end]>=dateadd(d,3,getdate()) then '促销'
        when datediff(d,[end],dateadd(d,3,getdate()))<2 then '回报日'
        when datediff(d,[end],dateadd(d,3,getdate()))<3 then '终止日'
        when datediff(d,[end],dateadd(d,3,getdate()))>=3 then '无效' end) as [T+3],
(case when start>dateadd(d,4,getdate()) then '准促销'
        when start<=dateadd(d,4,getdate()) and [end]>=dateadd(d,4,getdate()) then '促销'
        when datediff(d,[end],dateadd(d,4,getdate()))<2 then '回报日'
        when datediff(d,[end],dateadd(d,4,getdate()))<3 then '终止日'
        when datediff(d,[end],dateadd(d,4,getdate()))>=3 then '无效' end) as [T+4]
 from tb
/*
start                   end                     T+0    T+1    T+2    T+3    T+4
----------------------- ----------------------- ------ ------ ------ ------ ------
2011-06-09 00:00:00.000 2011-06-11 00:00:00.000 促销     促销     回报日    回报日    终止日
2011-06-08 00:00:00.000 2011-06-10 00:00:00.000 促销     回报日    回报日    终止日    无效
2011-06-10 00:00:00.000 2011-06-11 00:00:00.000 准促销    促销     回报日    回报日    终止日

(3 行受影响)
*/
go
drop table tb

恩，是您这样的意思。好像有些瑕疵：因为‘回报日’和‘终止日’在每行里[每个起止时间段]各只会出现一次['准促销'和'促销'才可能会出现多次]。
(PS:另外：好像可以在每个判断前首先加上：WHEN start IS NULL THEN '准促销' .)

晚安，明天上午结贴.

SQL code

create table tb(start datetime,[end] datetime)
insert into tb
select '2011-06-09','2011-06-11' union all
select '2011-06-08','2011-06-10' union all
select '2011-06-10','2011-06-11'
go
declare @dt datetime
set @dt=convert(varchar(10),getdate(),120)
select *,
(case when start>@dt then '准促销'
        when start<=@dt and [end]>=@dt then '促销'
        when datediff(d,[end],@dt)<=1 then '回报日'
        when datediff(d,[end],@dt)<=2 then '终止日'
        when datediff(d,[end],@dt)>2 then '无效' end) as [T+0],
(case when start>dateadd(d,1,@dt) then '准促销'
        when start<=dateadd(d,1,@dt) and [end]>=dateadd(d,1,@dt) then '促销'
        when datediff(d,[end],dateadd(d,1,@dt))<=1 then '回报日'
        when datediff(d,[end],dateadd(d,1,@dt))<=2 then '终止日'
        when datediff(d,[end],dateadd(d,1,@dt))>2 then '无效' end) as [T+1],
(case when start>dateadd(d,2,@dt) then '准促销'
        when start<=dateadd(d,2,@dt) and [end]>=dateadd(d,2,@dt) then '促销'
        when datediff(d,[end],dateadd(d,2,@dt))<=1 then '回报日'
        when datediff(d,[end],dateadd(d,2,@dt))<=2 then '终止日'
        when datediff(d,[end],dateadd(d,2,@dt))>2 then '无效' end) as [T+2],
(case when start>dateadd(d,3,@dt) then '准促销'
        when start<=dateadd(d,3,@dt) and [end]>=dateadd(d,3,@dt) then '促销'
        when datediff(d,[end],dateadd(d,3,@dt))<=1 then '回报日'
        when datediff(d,[end],dateadd(d,3,@dt))<=2 then '终止日'
        when datediff(d,[end],dateadd(d,3,@dt))>2 then '无效' end) as [T+3],
(case when start>dateadd(d,4,@dt) then '准促销'
        when start<=dateadd(d,4,@dt) and [end]>=dateadd(d,4,@dt) then '促销'
        when datediff(d,[end],dateadd(d,4,@dt))<=1 then '回报日'
        when datediff(d,[end],dateadd(d,4,@dt))<=2 then '终止日'
        when datediff(d,[end],dateadd(d,4,@dt))>2 then '无效' end) as [T+4]
 from tb
/*
start                   end                     T+0    T+1    T+2    T+3    T+4
----------------------- ----------------------- ------ ------ ------ ------ ------
2011-06-09 00:00:00.000 2011-06-11 00:00:00.000 促销     促销     促销     回报日    终止日
2011-06-08 00:00:00.000 2011-06-10 00:00:00.000 促销     促销     回报日    终止日    无效
2011-06-10 00:00:00.000 2011-06-11 00:00:00.000 准促销    促销     促销     回报日    终止日

(3 行受影响)
*/
go
drop table tb