Let's say we want to add a new user "Erick Broski" with SELECT privileges on database "userlistdb".
mysql> grant SELECT on userlistdb.* to 'erick.broski'@'localhost';
Make sure to set his password:
mysql> set password for 'erick.broski'@'localhost'= password('h@ckm3');
Now, lets say we want to give "Erick Broski" all privileges on database "ssnumbersdb".
mysql> grant ALL PRIVILEGES on ssnumbersdb.* to 'erick.broski'@'localhost';
Additionally, we can limit the access to a DB by the user's IP.
mysql> RENAME USER 'erick.broski'@'localhost' TO 'erick.broski'@'192.168.%';
Show all users.
mysql> SELECT user FROM mysql.user;