mysql - 我如何只退回那些欠我钱的客户（在 mySQL 中）？

Question

我有一个客户表和一个付款表，它们在客户 ID (CID) 上连接。在 Payment 表中有一个 Amount 列；有些行的金额为正数（他们欠钱），但其他行的金额为负数（他们付了钱）。

我想知道哪些客户，当我将他们的正数和负数相加时，仍然欠我钱。

如果我只是想查看他们的余额，我可以这样做：

SELECT Customer.FirstName, Customer.LastName, Customer.AccountNumber, SUM(Amount) As Balance
FROM Customer
 JOIN Payment
   ON Customer.CID = Payment.CID
GROUP BY Customer.AccountNumber

如何更改此设置，以便如果余额为 0 或更少，我不会为该客户返回一行？

编辑： HAVING是我不知道的关键字。感谢您的许多正确答案！

Answer 1

SELECT Customer.FirstName, Customer.LastName, Customer.AccountNumber, SUM(Amount) As Balance
FROM Customer
 JOIN Payment
   ON Customer.CID = Payment.CID
GROUP BY Customer.AccountNumber
HAVING Balance>0

Answer 2

HAVING 关键字允许您根据功能分组进行选择：

SELECT Customer.FirstName, Customer.LastName, Customer.AccountNumber, SUM(Amount) As Balance
FROM Customer
JOIN Payment
ON Customer.CID = Payment.CID
GROUP BY Customer.AccountNumber
HAVING SUM(Amount) > 0

Answer 3

SELECT c.FirstName, c.LastName, c.AccountNumber, p.Amount AS Balance
FROM Customer c 
JOIN Payment p
ON c.CID = p.CID
GROUP BY c.AccountNumber
HAVING SUM(p.Amount) > 0

Answer 4

select customers.name, sum(payments.amount) balance  
from customers join payments on customers.id = payments.cid
group by customers.id having balance > 0