Question

有一个名为r_no的列，它是与日期列

关联的三个重复值

r_no         date values
1            09-Apr-2016  03:49:24
1            09-Apr-2016 03:49:30 
1            09-Apr-2016 03:49:40

我希望输出为：

1 09-Apr-2016 03:49:40

删除具有最新日期值的重复值

Answer 1

假设您正在使用Microsoft SQL Server：

SELECT TOP 1 ID, DATE FROM #TEMP ORDER BY DATE DESC

删除＆amp;显示最新的：

;WITH TTT AS
(
 SELECT ROW_NUMBER() OVER(PARTITION BY ID ORDER BY ID)SR, DATE, ID FROM #TEMP
) 

DELETE  FROM TTT WHERE DATE NOT IN(SELECT MAX(DATE) FROM TTT)

SELECT * FROM #TEMP

说明： CTE将获取所有记录并为每个唯一条目应用行号。每个附加条目都将获得递增数字。

Answer 2

您可以直接从CTE表达式delete dublicate data使用Row_Number（）函数，如下所示

;with cte as (
select 
    r_no, [date values],
    ROW_NUMBER() over (partition by r_no order by [date values] desc) as rn
from temptbl
)
delete from cte where rn > 1

Answer 3

您可以使用OUTER APPLY。

执行此操作

SELECT DISTINCT yt.r_no, oa.[date values]
FROM YourTable yt
OUTER APPLY (SELECT TOP 1 [date values]
             FROM YourTable
             WHERE r_no = yt.r_no
             ORDER BY [date values] DESC) oa

您也可以使用嵌入式查询执行此操作。

SELECT DISTINCT *
FROM YourTable yt
WHERE [date values] = (SELECT MAX([date values]) FROM YourTable WHERE r_no = yt.r_no)

删除列中的重复值

3 个答案: