为什么这个SQL代码会给出错误1066（不唯一的表/别名：'customer'）？

Question

为什么下面的MySQL查询会给出错误1066 (Not unique table/alias: '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customer声明中列出了FROM 两次表格。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