Question

我有三张桌子：

Bank_Account(Tran_Id, Pay_Id, Expense_Id, Amount, Balance) 
Payment(Pay_Id, Client_Id, Date_Payment, Amount) 
Expense(Expense_Id, Emp_Id, Amount, Expense)

其中Tran_Id是Bank_Account的主键，Pay_Id的{{1}}和Payment的{{1}}也是如此。在Expense_Id Expense时Bank_Account为Pay_Id为空，反之亦然。现在我想用Expense_Id来计算公司的利润。那么我该如何使用SQL脚本来计算（Bank_Account基于金额的总和 - 基于Pay_Id金额的总和。

Answer 1

我认为，这应该是你的陈述，但我想，你错过了一个要在你的Bank_Account表（即公司）中分组的字段。你想知道，公司的金额，还是？

SELECT <missingFieldCompany>, SUM(Payment.Amount) as Payments, SUM(Expense.Amount) as Expenses, SUM(Payment.Amount) - SUM(Expense.Amount) as Overall
FROM Bank_Account 
LEFT JOIN Payment ON Payment.Pay_Id = Bank_Account.Pay_Id
LEFT JOIN Expense ON Expense.Expense_Id = Bank_Account.Expense_Id
GROUP BY <missingFieldCompany>

Answer 2

试试这个：

select 
    SUM(Amount * (Pay_Id IS NOT NULL)) AS PayIdAmt,
    SUM(Amount * (Expense_Id IS NOT NULL)) AS ExpenseIdAmt
FROM Bank_Account

Answer 3

SELECT SUM(p.Amount) as payments, SUM(e.Amount) as expenses,  
SUM(p.Amount) - SUM(e.Amount) as total_amount
FROM Bank_Account as b
LEFT JOIN Payment as p ON p.Pay_Id = b.Pay_Id
LEFT JOIN Expense as e ON e.Expense_Id = b.Expense_Id

Answer 4

在下面尝试更多信息后，查询工作对我来说.....

选择（b2.total2 - b1.total1）为总数从（选择SUM（金额）为Bank_Account中的total1，其中Pay_Id为NULL）b1，（SELECT SUM（金额）为Bank_Account中的total2，其中Pay_Id为非NULL）b2

MySQL特定列添加

4 个答案: