How to create a user
CREATE USER 'myuser'@'localhost' IDENTIFIED BY 'mypassword';
How to delete a user
DROP USER 'myuser'@'localhost';
How to grant permissions
GRANT ALL PRIVILEGES ON * . * TO 'myuser'@'localhost';
How to apply those permissions
FLUSH PRIVILEGES;
Going a bit deeper
Different types of Grants
ALL PRIVILEGES : Full access to everything, globally unless restricted to a database
CREATE : Create databases and tables
DROP : Delete databases and tables
DELETE : Delete rows from tables
INSERT : Insert rows in tables
SELECT : Read data from tables
UPDATE : Update rows in tables
GRANT OPTION : Grant or remote other user’s permissions
How to use them
GRANT permission_type ON database_name.table_name TO 'myuser'@'localhost';
How to revoke them
REVOKE permission_type ON database_name.table_name FROM 'myuser'@'localhost';
How to show them
SHOW GRANTS myuser;