How to understand mysql federated query

This article introduces the relevant knowledge of "how to understand mysql federated query". In the operation of actual cases, many people will encounter such a dilemma. Next, let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

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; that's all for "how to understand mysql federated query". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!