续其他同伙与类别

Question

我想指望所有记录的最新记录同一类别的纪录属于一个类别&得到了最新的纪录

CREATE TABLE #TestTable 

(

SomeColumn VARCHAR(1) 
,data varchar(50) 
,CDate datetime 
) 

GO 

INSERT INTO #TestTable VALUES ('A','abdss',getdate()) 
INSERT INTO #TestTable VALUES ('A','abserts',getdate()) 
INSERT INTO #TestTable VALUES ('A','awabs',getdate()) 
INSERT INTO #TestTable VALUES ('A','abrfgts',getdate()) 
INSERT INTO #TestTable VALUES ('A','abasds',getdate()) 
INSERT INTO #TestTable VALUES ('A','abasds',getdate()) 
INSERT INTO #TestTable VALUES ('A','aberzsdsfs',getdate()) 
INSERT INTO #TestTable VALUES ('A','abarfzdfs',getdate()) 
INSERT INTO #TestTable VALUES ('B','abzdsfs',getdate()) 

--SELECT * , COUNT(SomeColumn) From #TestTable 
--GROUP BY SomeColumn 

drop table #TestTable 

相关的数据所需的输出将是

SomeColumn | Data   | Date    |Other Associates Records <br/> 
A   | abarfzdfs  |last A record date |7<br/> 
B   | abzdsfs  |last B record date |0<br/> 

Answer 1

您还没有指定您使用的是哪个版本的sql server。但是如果你使用的是sql-server 2005+。也许是这样的：

;WITH CTE 
AS 
(
    SELECT 
     ROW_NUMBER() OVER(PARTITION BY SomeColumn ORDER BY CDate) AS RowNbr, 
     COUNT(SomeColumn) OVER(PARTITION BY SomeColumn) AS Counts, 
     test.* 
    FROM 
     #TestTable AS test 
) 
SELECT 
    * 
FROM 
    CTE 
WHERE 
    CTE.RowNbr=1