How to define mysql federated query

This article mainly introduces the relevant knowledge of "how to define mysql federated query". The editor shows you the operation process through an actual case. The operation method is simple, fast and practical. I hope this article "how to define mysql federated query" can help you solve the problem.

1, also known as join query, join the data in multiple tables to obtain the result set. When a table cannot satisfy the query results, a federated query is required.

2. Premise that there must be logical correlation between federated tables.

Example

-- example: select orders.order_id, orders.amt, customer.cust_name, customer.tel_nofrom orders, customerwhere orders.cust_id = customer.cust_id;-- alias select a.order_id, a.amt, b.cust_name, b.tel_nofrom orders a, customer bwhere a.cust_id = b.custchild; this is the end of the introduction on "how to define mysql federated query". Thank you for your reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.