一個SQL排序的問題[轉]

create table #tb (id int,User1 nvarchar(100),ProductName nvarchar(100),AddTime smalldatetime)

---第一次:每一个用户按最新日期取一条排到前面

---第二次:其它产品直接按日期最新日期排!

insert into #tb
          select 1,  'A'  ,       'AAB',        '2006-1-1'
union all select 2,  'A'  ,       'BBD',        '2006-1-4'
union all select 3,  'B'  ,       'CCA',        '2006-9-8'
union all select 4,  'B'  ,       'DDD',        '2006-8-5'
union all select 5,  'C'  ,       'EEf',        '2006-9-5'
union all select 6,  'C'  ,       'fff',        '2006-9-6'

select * from #tb a order by case when exists(select 1 from #tb where a.user1=user1 and a.addtime>addtime)
 then 1 else 2 end ,addtime desc

結果:

3 B CCA 2006-09-08 00:00:00
6 C fff 2006-09-06 00:00:00
2 A BBD 2006-01-04 00:00:00
5 C EEf 2006-09-05 00:00:00
4 B DDD 2006-08-05 00:00:00
1 A AAB 2006-01-01 00:00:00