需要SQL查询/子查询帮助

Question

我试图从SQL Server 2005上的测试信息表中获取最近10个序列号的列表.我尝试过这样的事情:

SELECT DISTINCT TOP (10) Serial, DateTime
FROM [Test].[dbo].[TestInfo]
WHERE (TestedBy = 'JSMITH') ORDER BY DateTime DESC

返回重复的序列:

+---------+-------------------------+
| Serial  | DateTime                |
+-----------------------------------+
| 1114048 | 2011-03-16 11:03:14.000 |
| 1617683 | 2011-03-11 15:07:29.000 |
| 1617683 | 2011-03-11 15:07:27.000 |
| 1617683 | 2011-03-11 15:07:26.000 |
| 1617683 | 2011-03-10 13:16:04.000 |
| 1617683 | 2011-03-10 13:15:35.000 |
| 1617683 | 2011-03-10 13:15:30.000 |
| 1617683 | 2011-03-07 13:42:48.000 |
| 1617683 | 2011-03-07 13:40:32.000 |
| 1617683 | 2011-03-07 13:37:58.000 |
+---------+-------------------------+

有没有办法,使用查询或子查询来获取最后10个没有重复的序列？

Answer 1

select top (10) Serial, Max(DateTime)
from [Test].[dbo].[TestInfo]
where (TestedBy = 'JSMITH')
group by Serial
order by Max(DateTime) desc