Question

我有以下两个表：

一下现金出纳机

Date    PaymentId  CustId  VenId  Debit  Credit  Date
=========================================================
2/2/12  Pay_1      Cus_1                 444     3/2/2012
4/2/12  Pay_2              Ven_1  555

SalesOrder

SaleOrderId  CustId  Debit  Credit
==================================
So_1         Cus_1   666

从这两个表格中，我必须生成期刊报告，如下所示：

Date    TrId    AccountId  Debit  Credit
========================================
2/2/12  Pay_1   Cus_1             444   
3/3/12  So_1    Cus_1      666
4/2/12  Pay_2   Ven_1      555

我试过这个问题：

 SELECT *
   FROM (
        SELECT Date, PaymentId, TrId, CustId, AccountId, VenId, AccountId, Debit,
               Credit
          FROM CashRegister

         UNION

        SELECT Date, SaleOrderId, TrId, CustId, AccountId, Debit, Credit
          FROM SalesOrder
        ) t
  ORDER BY Date

但它给出了这个错误：

对于目标列表，联合表达式的数量应相等。

Answer 1

要更正您的查询，您必须添加存根列（null是通常的存根值），例如

   select * 
     from (select Date,
                  PaymentId TrId,
                  CustId AccountId,
                  VenId, 
                  Debit,
                  Credit 
             from CashRegister

            union

           select Date,
                  SaleOrderId TrId,
                  CustId AccountId,
                  null,  -- Stub: there's no verdor id
                  Debit,
                  Credit
             from SalesOrder) t 
order by Date

然而，似乎正确的查询（返回所需的光标）是

    select Date,
           PaymentId as TrId, 
           Coalesce(CustId, VenId) as AccountId, -- if CustId is null take VenId
           Debit, 
           Credit 
      from CashRegister
 union all -- I don't think you want to remove occasional dublicates
    select Date, 
           SaleOrderId,
           CustId, 
           Debit,
           Credit
      from SalesOrder
  order by Date

Answer 2

您似乎想要使用CashRegister表中的CustId或VenId，如果是这样，我认为这就是您想要的：

SELECT 
    Date, 
    PaymentId AS TrId, 
    COALESCE(CustId, VenId) AS AccountId,  -- COALESCE returns the first 
    Debit,                                 -- non null value as AccountId
    Credit     
FROM CashRegister
UNION -- use UNION ALL if you don't want to eliminate duplicate rows.
SELECT 
    Date, 
    SaleOrderId, 
    CustId, 
    Debit, 
    Credit
FROM SalesOrder
ORDER BY Date

示例SQL Fiddle

Answer 3

您似乎想要使用CashRegister表中的CustId或VenId，如果是这样，我认为这就是您想要的： SELECT Date, PaymentId AS TrId, if(CustId<>'',CustId, VenId) AS AccountId, Debit, Credit FROM CashRegister UNION SELECT Date, SaleOrderId AS TrId, CustId AS AccountId, Debit, Credit FROM SalesOrder order by Date;

编辑：堆栈溢出格式化已剥离“＆lt;＆gt;”从我的代码。这将处理CustID beiang空文本，而不仅仅是CustID为NULL。

如何从具有不同布局的两个表中选择列

3 个答案: