如何选择日期时间值的最大值 [英] how to select Maximum value of datetime value

问题描述

我的表是：

My table is:

ProcessMode ProcessDate ProcessTime CardNo  EffectiveDate   EffectiveTime   ExpireDate  ExpireTime  HolderName  EffectiveDate1
1   12/21/2011  10:04:14    0749    12/21/2011  00:00           Martin Francis 1366
1   12/21/2011  10:06:04    0749    12/21/2011  00:00           Martin Francis 1366
1   07/09/2013  13:00:14    0749    07/09/2013  00:00           Martin Francis 1366
1   07/09/2013  14:33:24    0749    07/09/2013  00:00           Martin Francis 1366
1   07/10/2013  12:42:58    0749    07/10/2013  12:30           Martin francis 1366
2   12/21/2011  10:30:20    0749            12/21/2011  10:30   Martin Francis 1366
2   07/09/2013  14:33:26    0749            07/09/2013  14:30   Martin Francis 1366
2   07/10/2013  12:30:03    0749            07/10/2013  12:30   Martin francis 1366
2   07/10/2013  13:23:15    0749            07/10/2013  13:00   Martin francis 1366
2   07/10/2013  14:28:59    0749            07/10/2013  14:00   Martin francis 1366
2   07/10/2013  14:59:23    0749            07/10/2013  14:30   Martin Francis 1366


I need to select the maximum value of EffectiveDate (MM/dd/yyyy).but that EffectiveDate  is taken in string value

 i Want Result would be:

ProcessMode	ProcessDate	ProcessTime	CardNo	EffectiveDate	EffectiveTime	ExpireDate	ExpireTime	HolderName	EffectiveDate1
1	07/10/2013	12:42:58	0749	07/10/2013	12:30			Martin francis 1366

但是我尝试了一个代码。

var AutoEffectExpireData =SELECT * FROM（SELECT AutoEffectExpireData.CardNo，Max（AutoEffectExpireData.EffectiveDate）AS EffectiveDate FROM AutoEffectExpireData GROUP BY AutoEffectExpireData.CardNo）AS CardNo INNER JOIN AutoEffectExpireData t1 ON CardNo.CardNo = t1.CardNo和CardNo.EffectiveDate = t1 .EffectiveDate ;





但输出是这样的。



ProcessMode ProcessDate ProcessTime CardNo EffectiveDate EffectiveTime ExpireDate ExpireTime HolderName EffectiveDate1

1 12/21/2011 10:04:14 0749 12/21/2011 00:00 Martin Francis 1366

but i tried one code.
var AutoEffectExpireData = " SELECT * FROM (SELECT AutoEffectExpireData.CardNo,Max(AutoEffectExpireData.EffectiveDate) AS EffectiveDate FROM AutoEffectExpireData GROUP BY AutoEffectExpireData.CardNo ) AS CardNo INNER JOIN AutoEffectExpireData t1 ON CardNo.CardNo = t1.CardNo and CardNo.EffectiveDate = t1.EffectiveDate ";


but output is came like this.

ProcessMode ProcessDate ProcessTime CardNo EffectiveDate EffectiveTime ExpireDate ExpireTime HolderName EffectiveDate1
1 12/21/2011 10:04:14 0749 12/21/2011 00:00 Martin Francis 1366

推荐答案

据我所知，如果你只需要最大生效日期，请尝试这个，

As i understand ur question if u only needs the max effective date then try this,

SELECT * FROM AutoEffectExpireData AEED  where datetime = (SELECT MAX(AEED.EffectiveDate) FROM topten AutoEffectExpireData
       GROUP BY clos..)Group by AEED.EffectiveDate ORDER BY AEED.EffectiveDate desc

hi ehsan，

请回复，但我需要知道您发送的查询中的Group By Clos ...

hi ehsan,
Thnks for the reply but i need to know what is Group By Clos... in the query which you have sent.

这篇关于如何选择日期时间值的最大值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！