基于两个变量的SQL DISTINCT

我试图消除客户ID和规则编号相同的重复值。。你知道怎样才能做到吗

谢谢

SELECT Violations_Temp.Temp_ID as 'ID', 
   Customers.Cust_Name as 'Homeowner', 
       Customers.Add1 as 'Unit', 
       Rules_Main.Rule_Number as 'Rule', 
        Violations_Temp.User_Name as 'Inspector', 
        DATE(Violations_Temp.Upload_TimeStamp) as 'Date', 
        Cast(Violations_Temp.Upload_TimeStamp as time) as 'Time'
        FROM Violations_Temp 
        JOIN Customers ON Customers.Customer_ID = Violations_Temp.Customer_ID 
        JOIN Rules_Main ON Rules_Main.Rules_ID = Violations_Temp.Violation_ID 

在回复Loc的消息时-您可以从结果中看到（除其他外）房主Adam White有多个记录，其中规则为11-我需要设置此项，以便仅为该组合返回一个记录

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（来源：）

这可能不是最优雅的方式，但它很有效。。。（当返回的数据加载到数据表中时）

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希望这个查询能起作用。我在这里使用了表别名：

SELECT C.*, T.Upload_TimeStamp, T.User_Name, X.Rule_Number
FROM Customers C,
     Violations_Temp T, 
     (SELECT
            T.Customer_ID,
            R.Rule_Number,
            MAX(T.Upload_TimeStamp) AS MAX_Upload_Timestamp 
      FROM 
        Violations_Temp T,
        Rules_Main R
      WHERE T.Violation_ID = R.Rules_ID
      GROUP BY C.Customer_ID, R.Rule_Number) X
WHERE
T.Customer_ID = C.Customer_ID
AND T.Customer_ID = X.Customer_ID
AND T.Upload_TimeStamp = X.MAX_Upload_Timestamp

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您的查询目的是什么？我已编辑查询以显示结果，但您没有重复项。每个ID都是不同的。除非你想从房主和规则那里得到它，否则没有办法做你想做的。我看不到任何重复的客户ID，规则编号。你不是说房主，规则编号吗？你必须定义一个重复的标准。例如，您是对的，对于客户adam white，规则11多次出现，但对于每个结果，都有一个唯一的

违规\u Temp.Upload\u TimeStamp

。我们应该保留哪一个？

SELECT C.*, T.Upload_TimeStamp, T.User_Name, X.Rule_Number
FROM Customers C,
     Violations_Temp T, 
     (SELECT
            T.Customer_ID,
            R.Rule_Number,
            MAX(T.Upload_TimeStamp) AS MAX_Upload_Timestamp 
      FROM 
        Violations_Temp T,
        Rules_Main R
      WHERE T.Violation_ID = R.Rules_ID
      GROUP BY C.Customer_ID, R.Rule_Number) X
WHERE
T.Customer_ID = C.Customer_ID
AND T.Customer_ID = X.Customer_ID
AND T.Upload_TimeStamp = X.MAX_Upload_Timestamp