Question

我有一个看起来像这样的表：（使用Sql-server 2012）

ID------------DAY----------HOUR--COMMENT

00050064 | 2015-09-30  | 14:41 | Creaci¢n de Pedido UD3503-0000001 ==> UD4003            
00050064 | 2015-09-30  | 11:52 | Se di¢ de alta el documento: UD4003-0000003                                     
00050064 | 2015-09-30  | 11:42 | Asignaci¢n de t‚cnico: MANUEL REGALADO                                          
00050064 | 2015-09-30  | 11:42 | Cambio de fecha y hora programa                   
00050064 | 2015-09-30  | 11:40 | SE PROGRAMARA POSTERIOR MENTE                      
00050064 | 2015-09-30  | 11:39 | PRUEBA NUMERO SERIE OS  ANALISIS

我设法按日期和时间排序结果，我可以看到最后一条评论，但问题是，由于我的ID不是唯一的，我不知道如何选择最新的评论。

我的疑问：

select * from
(
select gdoshistorial.c1 as ID,max(gdoshistorial.c3) as [DAY],
max(gdoshistorial.c4) as [TIME], gdoshistorial.c6 AS COMMENT from gdos   
left join gdoshistorial on GDOSHISTORIAL.c1 = gdos.c1
where gdos.c1 = gdoshistorial.c1 and gdoshistorial.c1 = '00050064'
group by GDOSHISTORIAL.c1,GDOSHISTORIAL.c6
)v

order by [ID],[DAY],[TIME] desc

请帮我找到一种方法来选择第一行并忽略重复的id's 期望的结果示例：

ID------------DAY----------HOUR--COMMENT

00050064 | 2015-09-30  | 14:41 | Creaci¢n de Pedido UD3503-0000001 ==> UD4003

而不是从同一个ID中获取大量评论，我只想查看最新的评论。

Answer 1

select id, date, hour, comment from
(
select row_number() over(partition by id, day order by hour desc) as rn,
* from gdoshistorial ) t
where rn = 1

您可以使用row_number获取每天的最新信息和身份证。

注意：上面的查询会为您提供每天的最新评论。如果您只需要最新的评论，无论白天，改变

row_number() over(partition by id, day order by hour desc) as rn

到

row_number() over(partition by id order by day desc, hour desc) as rn

Answer 2

SELECT TOP 1 *
FROM (
    SELECT gdoshistorial.c1 AS ID
        ,max(gdoshistorial.c3) AS [DAY]
        ,max(gdoshistorial.c4) AS [TIME]
        ,gdoshistorial.c6 AS COMMENT
    FROM gdos
    LEFT JOIN gdoshistorial ON GDOSHISTORIAL.c1 = gdos.c1
    WHERE gdos.c1 = gdoshistorial.c1
        AND gdoshistorial.c1 = '00050064'
    GROUP BY GDOSHISTORIAL.c1
        ,GDOSHISTORIAL.c6
    ) v
ORDER BY 
     [DAY] DESC
    ,[TIME] DESC

当ID不唯一时，选择表上的最新评论

2 个答案: