获取基础上的一个

Question

MAX日，所有列的显着成果使用SQL Server 2012

我已经看到了关于该主题的几个线程，但我不能找到一个涉及查询多个连接。我无法在此数据库上创建VIEW，因此需要连接。

查询

SELECT 

     p.Price 
     ,s.Type 
     ,s.Symbol 
     , MAX(d.Date) Maxed 
    FROM AdventDW.dbo.FactPrices p 
    INNER JOIN dbo.DimSecurityMaster s 
    ON s.SecurityID = p.SecurityID 
    INNER JOIN dbo.DimDateTime d 
    ON 
    p.DateTimeKey = d.DateTimeKey 
    GROUP BY p.Price , 
      s.Type , 
      s.Symbol 
ORDER BY s.Symbol 

查询工作，但并没有产生明显的效果。我正在使用Order by来验证结果，但是一旦我开始工作，就不需要它了。我结果集看起来像这样。

Price Type Symbol Maxed 
10.57 bfus *bbkd   3/31/1989 
10.77 bfus *bbkd   2/28/1990 
100.74049 cbus 001397AA6  8/2/2005 
100.8161 cbus 001397AA6  7/21/2005 

的结果集我要的是

Price Type Symbol Maxed 
10.77 bfus *bbkd   2/28/1990 
100.74049 cbus 001397AA6  8/2/2005 

这里是一些其他StackOverflow的线程我试过，但不能用我特定的查询得到牛逼工作

How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?

SQL Selecting distinct rows from multiple columns based on max value in one column

Answer 1

如果您想要数据为格言嗯日期，使用row_number()而不是group by：

SELECT ts.* 
FROM (SELECT p.Price, s.Type, s.Symbol, d.Date, 
      ROW_NUMBER() OVER (PARTITION BY s.Type, s.Symbol 
           ORDER BY d.Date DESC 
           ) as seqnum 
     FROM AdventDW.dbo.FactPrices p INNER JOIN 
      dbo.DimSecurityMaster s 
      ON s.SecurityID = p.SecurityID INNER JOIN 
      dbo.DimDateTime d 
      ON p.DateTimeKey = d.DateTimeKey 
    ) ts 
WHERE seqnum = 1 
ORDER BY s.Symbol; 

Answer 2

您应该使用派生表，因为你真的只想组DateTimeKey表来获得MAX日期。

SELECT p.Price , 
     s.Type , 
     s.Symbol , 
     tmp.MaxDate 
FROM AdventDW.dbo.FactPrices p 
INNER JOIN dbo.DimSecurityMaster s ON s.SecurityID = p.SecurityID 
INNER JOIN 
    (SELECT MAX(d.Date) AS MaxDate , 
      d.DateTimeKey 
    FROM dbo.DimDateTime d 
    GROUP BY d.DateTimeKey) tmp ON p.DateTimeKey = tmp.DateTimeKey 
ORDER BY s.Symbol; 

Answer 3

/* 
    this is your initial select which is fine because this is base from your original criteria, 
I cannot ignore this so i'll keep this in-tact. Instead from here i'll create a temp 
    */ 

    SELECT 
     p.Price 
     , s.Type 
     , s.Symbol 
     , MAX(d.Date) Maxed 
    INTO #tmpT 
    FROM AdventDW.dbo.FactPrices p 
    INNER JOIN dbo.DimSecurityMaster s 
     ON s.SecurityID = p.SecurityID 
    INNER JOIN dbo.DimDateTime d 
     ON p.DateTimeKey = d.DateTimeKey 
    GROUP BY p.Price , 
     s.Type , 
     s.Symbol 
    ORDER BY s.Symbol 

SELECT innerTable.Price, innerTable.Symbol, innerTable.Type, innerTable.Maxed 
FROM (

    SELECT 
     ROW_NUMBER() OVER (PARTITION BY t1.Symbol, t1.Type, t1.Maxed ORDER BY t1.Maxed DESC) as row 
     , * 
    FROM #tmpT AS t1 
) AS innerTable 
WHERE row = 1 

DROP TABLE #tmpT