May 15, 2021

Last Updated on 2021-05-15 by Clay

There are usually several tables in a database, and there are many data stored. In addition to query the data, if we are the database administrator, we also need to know how to "add", "modify", "delete" the table and the fields and data in the table.

Last Updated on 2021-05-15 by Clay

I briefly mentioned that the WHERE instruction can be used as an IF conditional judgment. Today, I will continue to record how to use WHERE.

Last Updated on 2021-05-15 by Clay

Today I record some commonly used instructions of SQL:

• AVG()
• COUNT()
• MAX()
• MIN()
• SUM()