Seeing each other and waiting for a while -- MySQL multi-table query _ MySQL

Seeing each other late -- MySQL multi-table queries do not use mathematical symbols to describe exercise questions about too many table queries when I remembered the database principles last semester. Now we use php to write the function point. to query a database involves multiple tables, we can implement multi-table queries without thinking about using SQL statements. The results are not good.

After thinking about it, google finally found the desired post.

Connection: http://honey505.blog.sohu.com/9487669.html

Mysql would have known this before, but I had to check it online...