查询具有最大的日期的一组多个记录....几分

Question

示例代码：

DECLARE @TABLE TABLE (ID int, Name varchar(50), Date Datetime2) 

INSERT INTO @TABLE (ID, Name, Date) 
SELECT 1, 'abc', GETDATE() 
UNION ALL 
SELECT 1, 'def', GETDATE() 
UNION ALL 
SELECT 1, 'hij', GETDATE() 
UNION ALL 
SELECT 1, 'abc', GETDATE()-2 
UNION ALL 
SELECT 1, 'def', GETDATE()-2 
UNION ALL 
SELECT 1, 'hij', GETDATE()-2 
UNION ALL 
SELECT 1, 'abc', GETDATE()-4 
UNION ALL 
SELECT 1, 'def', GETDATE()-4 
UNION ALL 
SELECT 1, 'hij', GETDATE()-4 
UNION ALL 
SELECT 2, 'abc', GETDATE()-1 
UNION ALL 
SELECT 2, 'def', GETDATE()-1 
UNION ALL 
SELECT 2, 'hij', GETDATE()-1 
UNION ALL 
SELECT 2, 'abc', GETDATE()-3 
UNION ALL 
SELECT 2, 'def', GETDATE()-3 
UNION ALL 
SELECT 2, 'hij', GETDATE()-3 
UNION ALL 
SELECT 2, 'abc', GETDATE()-4 
UNION ALL 
SELECT 2, 'def', GETDATE()-4 
UNION ALL 
SELECT 2, 'hij', GETDATE()-4 
UNION ALL 
SELECT 3, 'abc', GETDATE()+2 
UNION ALL 
SELECT 3, 'def', GETDATE()+2 
UNION ALL 
SELECT 3, 'hij', GETDATE()+2 
UNION ALL 
SELECT 3, 'abc', GETDATE()-4 
UNION ALL 
SELECT 3, 'def', GETDATE()-4 
UNION ALL 
SELECT 3, 'hij', GETDATE()-4 
UNION ALL 
SELECT 3, 'abc', GETDATE()-5 
UNION ALL 
SELECT 3, 'def', GETDATE()-5 
UNION ALL 
SELECT 3, 'hij', GETDATE()-5 
UNION ALL 
SELECT 4, 'abc', GETDATE()+1 
UNION ALL 
SELECT 4, 'def', GETDATE()+1 
UNION ALL 
SELECT 4, 'hij', GETDATE()+1 
UNION ALL 
SELECT 4, 'abc', GETDATE()-4 
UNION ALL 
SELECT 4, 'def', GETDATE()-4 
UNION ALL 
SELECT 4, 'hij', GETDATE()-4 
UNION ALL 
SELECT 4, 'abc', GETDATE()-5 
UNION ALL 
SELECT 4, 'def', GETDATE()-5 
UNION ALL 
SELECT 4, 'hij', GETDATE()-5 

SELECT * FROM @TABLE 

数据输出，我想反映以下记录

3 abc 2013-09-18 
3 def 2013-09-18 
3 hij 2013-09-18 

描述输出：我想要查询最近处理过的ID /名称的数据（最大（日期））（如果它们在相同的日期/时间处理，可以有多个ID）

我的尝试...

SELECT DISTINCT A.*, B.My_Rank 
FROM @TABLE A 
     INNER JOIN 
     (
      SELECT DISTINCT ID, Name, CONVERT(varchar(8), Date, 101) AS Date, RANK() OVER (PARTITION BY ID, Name ORDER BY CONVERT(varchar(8), Date, 101) DESC) My_Rank, MAX(CONVERT(varchar(8), Date, 101)) OVER (partition by ID, Name) Max_Date 
      FROM @TABLE 
      GROUP BY ID, Name, CONVERT(varchar(8), Date, 101) 
     ) B 
ON A.ID = B.ID AND CONVERT(varchar(8), A.Date, 101) = B.Max_Date 
WHERE My_Rank = 1 

显然，这种逻辑是不工作的。 “我想根据最新的处理ID /名称以获取ID /姓名/日期记录

谢谢

Answer 1

你接近，但你没有加入背部（你可能不希望PARTITION BY ID：

SELECT * 
FROM 
(
    SELECT ID, Name, Date, 
     RANK() OVER (ORDER BY CAST(Date AS DATE) DESC) My_Rank 
    FROM @TABLE 
) dt 
WHERE My_rank = 1  

AFAIK SS2008支持CAST（x AS DATE）

Answer 2

您想使用max()与partition by条款：

SELECT * 
FROM (select a.*, 
      max("date") over (partition by id) as maxdate 
     from @TABLE A 
    ) a 
where "date" = maxdate; 

这可以返回多行如果你只有一个人，甚至当有关系，然后使用row_number()：

SELECT * 
FROM (select a.*, 
      row_number() over (partition by id order by "date" desc) as seqnum 
     from @TABLE A 
    ) a 
where seqnum = 1;