为什么此 SQL 代码会给出错误 1066（不是唯一的表/别名：“客户”）？

Question

为什么下面的 MySQL 查询会给出错误 1066（不是唯一的表/别名：'customer'）？

SELECT customer.id, customer.firstName, account.id
FROM customer, account
INNER JOIN customer
ON customer.id = account.customerId 
ORDER BY customer.id

Answer 1

您已在 FROM 语句中两次列出了表customer。这是固定版本：

SELECT customer.id, customer.firstName, account.id
FROM account
INNER JOIN customer
ON customer.id = account.customerId
ORDER BY customer.id