Sql server 连接两个表的结果不正确

以下是给出错误结果的SQL查询

Select  ASXCode.Stock_Code, Count(Bought.Number_Bought) as Transactions, 
        SUM(Bought.Number_Bought) as Bought,
        SUM(Bought.Total_Cost) / SUM(Bought.Number_Bought) AS Average_Price,
        SUM(Bought.Acc_Interest) as Interest,
        SUM(Income.Total_Income) / COUNT(Bought.Number_Bought) as Derived_Income,  
        Sum(Bought.Total_Cost + Bought.Acc_Interest + Income.Neg_Total_Income) / SUM(Bought.Number_Bought) as Breakeven
FROM 
    ASXCode 
  LEFT JOIN 
    Bought ON Bought.Stockid = ASXCode.Stockid
  LEFT JOIN 
    Income ON ASXCode.Stockid = Income.Incomeid
GROUP BY 
    ASXCode.Stock_Code

上述SQL查询在DataGridview中产生如下结果：

 Stock_Code|Transactions|Bought|Average_Price|Interest|Derived_Income| Breakeven   
      ASL         2      10000      0.45       15.00                                                                           
      RCR         2       5000      1.90       55.35   
      SKE         6      20000      1.27      148.97    1071.43        0.96 

---

此表有两个问题。在计算盈亏平衡价格时，总收入乘以交易数量。正确的盈亏平衡价格约为1.22。如果我可以添加“除以COUNT Number_行的总和”，则查询的这一部分可以修复。但是，我没有成功地将其包含在查询中。第二，由于其他两种股票没有收入，收入字段为空，我认为这使得不可能计算盈亏平衡价格。我认为这个问题可以通过在查询中包含“where income not null”来解决。然而，尽管我做了各种尝试，试图在查询中包含这样一个语句，我还是画了一个空白。我真的很想找到解决我问题的办法。

我想你的问题来自于你有一个主表和两个细节表，如下所示：

[ Bought ] *-------1 [ ASXCode ] 1-------* [ Income ]

SELECT *
FROM ASXCode AS A
    LEFT OUTER JOIN
    (SELECT *
     FROM Bought
     GROUP BY *) AS B ON A.PK = B.FK
    LEFT OUTER JOIN
    (SELECT *
     FROM Income
     GROUP BY *) AS I ON A.PK = I.FK

因此，当您需要一个基于

ASXCode

的结果，并在

bunded

上详细说明时，不需要与

Income

交叉，反之亦然；您需要这样的查询：

[ Bought ] *-------1 [ ASXCode ] 1-------* [ Income ]

SELECT *
FROM ASXCode AS A
    LEFT OUTER JOIN
    (SELECT *
     FROM Bought
     GROUP BY *) AS B ON A.PK = B.FK
    LEFT OUTER JOIN
    (SELECT *
     FROM Income
     GROUP BY *) AS I ON A.PK = I.FK

因此，对于您来说，我认为这个查询应该正确工作：

SELECT
    A.Stock_Code, 
    B.Count_Number_Bought as Transactions, 
    B.SUM_Number_Bought as Bought,
    B.SUM_Total_Cost / B.SUM_Number_Bought AS Average_Price,
    B.SUM_Acc_Interest as Interest,
    I.SUM_Total_Income / B.Count_Number_Bought as Derived_Income,  
    (B.SUM_Total_Cost + B.SUM_Acc_Interest + I.SUM_Neg_Total_Income) / B.SUM_Number_Bought as Breakeven
FROM 
    ASXCode AS A
  LEFT JOIN 
    (SELECT 
         Bought.Stockid,
         COUNT(Bought.Number_Bought) As COUNT_Number_Bought,
         SUM(Bought.Number_Bought) AS SUM_Number_Bought,
         SUM(Bought.Total_Cost) AS SUM_Total_Cost,
         SUM(Bought.Acc_Interest) AS SUM_Acc_Interest
     FROM 
         Bought 
     GROUP BY 
         Bought.Stockid) AS B ON B.Stockid = A.Stockid
  LEFT JOIN
    (SELECT 
         Income.Stockid,
         SUM(Income.Total_Income) AS SUM_Total_Income,
         SUM(Income.Neg_Total_Income) AS SUM_Neg_Total_Income
     FROM
         Income 
     GROUP BY
         Income.Stockid) AS I ON A.Stockid = I.Stockid

---

看看查询在没有聚合和分组依据的情况下返回的结果。另外，在incomeid上加入stockid实际上是您想要的吗？什么是基数添加一个小样本数据集。如果我知道收入模式，我想我可以提供一个更好的解决方案，但我猜对于给定的stockid有一个行项目，对吗？如果是这种情况，请使用相同的查询创建一个CTE，但不包括对收入的引用。然后，加入CTE获得收入。这将解决第一个问题。我是一个完全的新手，你的表达CTE是我第一次听到它。一个快速的谷歌搜索提供了简短的信息，我将进一步研究这一点。ASXCode表连接到购买表和收入表。我已在以下链接上载了架构：Inchttps://www.flickr.com/photos/133286229@N02谢谢您提供的信息。关于数据库的结构，您是正确的。然而，您关于收入FK的评论强调（我认为）我的数据库构建中存在错误。我现在想知道我的FK是否命名错误？我已将我的数据库模式上载到@Johnkg。我将我的查询编辑为您的模式，希望它能为您提供正确的结果；）。shAt，我忘了提到我无法运行您的查询，并收到一条消息“关键字“ON”附近的语法不正确：”这使我相信我的数据库本身有问题。@Johnkg我想现在应该删除它；）。现在，我已经上传了（同一链接）我的交易详情的datagridview和这些交易的合并视图，而不需要将查询加入收入表。我还上传了您提供的查询解决方案的结果。正如您将看到的，收入已除以交易数量，没有任何收入的交易不进行计算。