1. Login to MySQL with root credentials
$ mysql -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 43 Server version: 5.5.49-0ubuntu0.14.04.1 (Ubuntu) Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
2. Create database mydb
mysql> create database mydb; Query OK, 1 row affected (0.00 sec)
3. Create user my_user
mysql> create user 'my_user'@"localhost" identified by "qwP3$5"; Query OK, 0 rows affected (0.00 sec)
4. Give all privileges to user my_user
mysql> grant all privileges on mydb.* to 'my_user' with grant option; Query OK, 0 rows affected (0.04 sec)
5. And then exit
mysql> exit Bye