Log in to MySQL database under Linux

mysql -u root -p

Enter and enter the password

1. Query all databases

mysql> show databases;

2. Use database ----XXX (XXX is the library name)

mysql> use XXX;

4. Query all tables

mysql> show tables;

Other operations (turn off the firewall and check the firewall status) 

systemctl stop firewalld
systemctl status firewalld