Question

我有三个单独的表：

SystemA_Cash
SystemA_Loans 
SystemB_CarLoans

每个表格都有Cash_AdvanceID字段，Customer和＆amp; Funded Amount。

我需要为每位客户提供总额。

每个客户也可以出现在任何表格中。

到目前为止我做了

SELECT SystemA_CashAdvances.CashAdvanceID, SystemA_CashAdvances.Customer, 
SystemA_CashAdvances.Funded_Amount 
FROM 
SystemA_CashAdvances
INNER JOIN
SystemA_Loans ON SystemA_Loans.CashAdvanceID = SystemA_CashAdvances.Cash_AdvanceID
INNER JOIN
SytemB_CarLoans ON SystemA_CashAdvances.Cash_AdvanceID = SystemB_CarLoans.CashAdvanceID;

它似乎没有与客户一起返回一张表，而且每笔表的总金额都已获得资助。

Answer 1

您可以使用UNION和GROUP BY，例如：

SELECT  Cash_AdvanceID,
        Customer, 
        SUM(Funded_Amount) AS "Total_Funded_Amount"
FROM (
        SELECT  Cash_AdvanceID,
                Customer, 
                Funded_Amount 
        FROM    SystemA_CashAdvances
        UNION
        SELECT  Cash_AdvanceID,
                Customer, 
                Funded_Amount 
        FROM    SystemA_Loans
        UNION
        SELECT  Cash_AdvanceID,
                Customer, 
                Funded_Amount 
        FROM    SytemB_CarLoans
)
GROUP BY Cash_AdvanceID,
         Customer;

使用JOIN执行此操作会很困难，因为MS Access不像其他数据库引擎那样支持完全外部联接。最接近的是单侧外连接，如下所示：

SELECT    a.Cash_AdvanceID,
          a.Customer, 
          a.Funded_Amount + Nz(l.Funded_Amount)
                          + Nz(c.Funded_Amount) AS "Total_Funded_Amount" 
FROM      (SystemA_CashAdvances AS a
LEFT JOIN SystemA_Loans AS l
       ON a.Cash_AdvanceID = l.Cash_AdvanceID)
LEFT JOIN SytemB_CarLoans AS c
       ON a.Cash_AdvanceID = c.Cash_AdvanceID;

以上内容适用于至少出现在 SystemA_CashAdvances 表中的客户。如果它们只出现在另一个表中，它们将被排除在结果之外。为了获得这些内容，您需要再次使用UNION，这会让我们回到上面的第一个解决方案。

已向每位客户提供的融资总额

1 个答案: