MS Access与类似字段组合表

Question

我想获得按日期排序的成本和付款的组合结果。这是我想查询：

SELECT ClientID, TheDate, Payment, Cost 
FROM 
(
    SELECT PaymentDate AS TheDate, Amount AS Payment, ClientID 
    FROM Payment 
    UNION ALL 
    SELECT BookedDate AS TheDate, Cost, ClientID 
    FROM [All Bookings Query] 
) 
ORDER BY TheDate DESC; 

它几乎运作...然而，弹出一个框，让我对“付款”（如字段不存在），输入一个值。如果我留下那个空白并点击确定，我会得到一个结果集，其中“Payment”列完全空白，而“Cost”列包含两个表中的金额。我使用的字段名称是100％正确的。

我认为问题在于UNION试图将两个表压缩成3列的结果，而我试图选择4.我从来没有做过这样的查询，所以我不知道如何解决这个问题。

我想要的是付款和成本分开的列。我的查询出了什么问题？

Answer 1

您需要在每个子查询中包含4列，将0列入付款的成本列，0列入预订的付款列。

SELECT ClientID, TheDate, Payment, Cost 
FROM 
(
    SELECT PaymentDate AS TheDate, Amount AS Payment, 0 AS Cost, ClientID 
    FROM Payment 
    UNION ALL 
    SELECT BookedDate AS TheDate, 0 As Payment, Cost, ClientID 
    FROM [All Bookings Query] 
) 
ORDER BY TheDate DESC;