1、进到数据库进行操作

[root@localhost etc]# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 7
Server version: 5.5.41-MariaDB MariaDB Server

Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> mysql
-> ;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds
to your MariaDB server version for the right syntax to use near 'mysql' at line 1MariaDB [(none)]> update user set password=password("123456")where user='root';
ERROR 1046 (3D000): No database selected
2、选择数据库

MariaDB [(none)]> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
3、用户root添加密码

MariaDB [mysql]> update user set password=password("tom_jk")where user='root';
Query OK, 0 rows affected (0.00 sec)
Rows matched: 4 Changed: 0 Warnings: 0
4、赋予权限

MariaDB [mysql]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
5、退出，重新登录

MariaDB [mysql]> exit
Bye
6、尝试无密码是否可以登录

[root@localhost etc]# mysql

提示错误

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
7、输入密码登陆

[root@localhost etc]# mysql -u root -p123456
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 5.5.41-MariaDB MariaDB Server

Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>