This is a ready reckoner for some of the commonly used commands for installation and maintenence of databases for wordpress:

Delete/Drop a database:

DROP DATABASE dbname;

Create a Database:

CREATE DATABASE  dbname;

Create a user:

CREATE USER IF NOT EXISTS 'username'@'localhost' IDENTIFIED BY 'newpassword';

Grant privileges to user on database:

GRANT ALL ON dbname.* TO 'username'@'localhost';
FLUSH PRIVILEGES;

List database users:

use mysql;
SELECT user FROM user;