如何获得排名靠前的日期和Id TSQL

Question

我有这个：

我无法弄清楚如何根据DomainId和最高日期获取行。

我想获得3行，每个唯一的domainId一行，它必须是domainId的最高日期

我的许多尝试之一：

SELECT DISTINCT 
    DomainId, DomainName, 
    Max([Date]), ServerOnline, DatabaseOnline, ServerPerformance, 
    DatabasePerformance, SoldTickets
FROM
    DomainDetailDataHistory
GROUP BY 
    DomainId, DomainName, ServerOnline, DatabaseOnline, 
    ServerPerformance, DatabasePerformance, SoldTickets

我该怎么做？

Answer 1

您有双标记 - 这适用于SQL Server：

SELECT * 
FROM ( SELECT DomainId, DomainName, [Date], serverOnline, DatabaseOnline, 
              ServerPerformance, DatabasePerformance, SoldTickets,
              ROW_NUMBER() OVER (PARTITION BY DomainId ORDER BY date DESC) AS rn
         FROM DomainDetailDataHistory 
     ) AS tt
WHERE tt.rn = 1

Answer 2

现在，您在GROUP BY语句的输出表中包含了所有内容，因此它将为相应列中每个唯一值组合返回一个新行。

首先尝试将DomainId和MAX([Date])关联到临时表中，然后INNER JOIN DomainId和[Date]上的表格。{/ p>

尝试以下方法：

DECLARE @Latest TABLE
(
    DomainId bigint, 
    [date] datetime2
)

INSERT INTO @Latest (DomainId, date)
SELECT DomainId, MAX(Date)
FROm DomainDetailDataHistory
GROUP BY DomainId


SELECT DISTINCT H.DomainId, DomainName,H.[Date],ServerOnline,DatabaseOnline, ServerPerformance, DatabasePerformance, SoldTickets
FROM DomainDetailDataHistory H
INNER JOIN @Latest T ON T.DomainId = H.DomainId AND T.[Date] = H.[Date]

Answer 3

这也可以，但仅当您使用 SQL Server 2012 + 时。

;WITH DomainDetailHistoryMax AS 
(
 SELECT 
 DomainId, DomainName, [Date], serverOnline, DatabaseOnline, 
          ServerPerformance, DatabasePerformance, SoldTickets
 ,LEAD([Date]) OVER (PARTITION BY DomainID ORDER BY [Date] ASC) AS cnt
 )
 SELECT 
 DomainId, DomainName, [Date], serverOnline, DatabaseOnline, 
          ServerPerformance, DatabasePerformance, SoldTickets
 FROM DomainDetailHistoryMax 
 WHERE cnt IS NULL;

https://msdn.microsoft.com/en-us/library/hh213125.aspx