Sql 如何自查询表以便从同一个表中获取最后执行的testcase

我正在使用MSSQL数据库SQL Server 2008 我必须查询数据库

select *, DateDiff(n,StartDateTime,EndDateTime) as DateDifference 
from result 
where   Project='Sample'  AND SubProject='Sample' and  
(StartDateTime)>='11/01/2013 00:00:00' AND (EndDateTime)<='11/11/2014 23:59:59'
order by EndDateTime desc

我想要enries，比如最后执行的测试用例

 TestCaseName        userName            StartDatetime           EndDateTime 
    poonam_tm_003   User1   2014-11-10 17:39:27.000 2014-11-10 17:39:31.000
    30SepTestCase   TM1 2014-10-29 10:12:09.000 2014-10-29 10:17:07.000

我只需要每个测试用例的最后一个实体。我指的是基于datediff的使用而具有maxEndDateTime的testcase，我假设您使用的是SQL Server。如果是这样，您可以使用row_number执行此操作：

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以下是一个可能有帮助的答案：

SELECT TestCaseName,
       userName,
       StartDatetime,
       EndDateTime,
       Datediff(N, StartDatetime, EndDateTime) AS datedifference
FROM   (SELECT *,
               ROW_NUMBER()
                 OVER (
                   partition BY testcasename
                   ORDER BY enddatetime DESC) AS rn
        FROM   yourtable) AS t
WHERE  Project = 'Sample'
       AND SubProject = 'Sample'
       AND ( StartDateTime ) >= '11/01/2013 00:00:00'
       AND ( EndDateTime ) <= '11/11/2014 23:59:59'
       AND rn = 1 

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我希望group by和max能合作

WITH CTE(Testcasename,userName,StartDatetime)
AS
(
SELECT Testcasename,userName,MAX(StartDatetime) StartDatetime
FROM result 
GROUP BY Testcasename,Username
)
SELECT A.*,DateDiff(DD,A.StartDateTime,A.EndDateTime) as DateDifference FROM 
RESULT A INNER JOIN CTE B ON A.Testcasename=B.Testcasename 
AND A.userName=B.userName
AND A.StartDatetime=B.StartDatetime
WHERE 
Project='Sample'  AND SubProject='Sample' and  
(A.StartDateTime)>='11/01/2013 00:00:00' AND (A.EndDateTime)<='11/11/2014 23:59:59'
order by A.EndDateTime desc

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请不要在评论中问你的问题。将这几点添加到您的问题中，并使问题更加清楚。您的查询结果是什么。您使用的是哪种DBMS？

SELECT TestCaseName,
       userName,
       StartDatetime,
       EndDateTime,
       Datediff(N, StartDatetime, EndDateTime) AS datedifference
FROM   (SELECT *,
               ROW_NUMBER()
                 OVER (
                   partition BY testcasename
                   ORDER BY enddatetime DESC) AS rn
        FROM   yourtable) AS t
WHERE  Project = 'Sample'
       AND SubProject = 'Sample'
       AND ( StartDateTime ) >= '11/01/2013 00:00:00'
       AND ( EndDateTime ) <= '11/11/2014 23:59:59'
       AND rn = 1 

WITH CTE(Testcasename,userName,StartDatetime)
AS
(
SELECT Testcasename,userName,MAX(StartDatetime) StartDatetime
FROM result 
GROUP BY Testcasename,Username
)
SELECT A.*,DateDiff(DD,A.StartDateTime,A.EndDateTime) as DateDifference FROM 
RESULT A INNER JOIN CTE B ON A.Testcasename=B.Testcasename 
AND A.userName=B.userName
AND A.StartDatetime=B.StartDatetime
WHERE 
Project='Sample'  AND SubProject='Sample' and  
(A.StartDateTime)>='11/01/2013 00:00:00' AND (A.EndDateTime)<='11/11/2014 23:59:59'
order by A.EndDateTime desc