mysql - 根据关系在帮助表中将两个表连接在一起

Question

我有两张 table

用户:电话号码，优惠券

客户:customer_id、优惠券

我想创建一个帮助表，根据特定的优惠券将 user 和 customer_id 链接在一起。第三个表将包含三个字段:coupon、phone_number、customer_id，它们应该从这两个表中检索。我试过 Inner Join 但似乎行不通。有人可以帮忙吗？

SELECT customers.customer_id as customer_id, users.phone as 
phone
FROM linked_customers_users 
INNER JOIN customers
ON linked_customers_users.customer_id = customers.customer_id
INNER JOIN users
ON linked_customers_users.phone = users.phone

Answer 1

尝试LEFT JOIN:

SELECT customers.customer_id as customer_id, users.phone as 
phone
FROM linked_customers_users 
LEFT JOIN customers
ON linked_customers_users.customer_id = customers.customer_id
LEFT JOIN users
ON linked_customers_users.phone = users.phone