Sistema de usuário - várias funções no banco de dados MySQL

User
--------------
id    name
 1    test

Role
--------------
id    name
 1    Donator
 2    Organizer
 3    Administrator

User_Role
--------------
id    user_id    role_id
 1    1          1
 2    1          3


SELECT * FROM User u 
    LEFT JOIN User_Role ur ON u.id = ur.user_id
    LEFT JOIN Role r ON ur.role_id = r.id
WHERE r.name = "Administrator";

SELECT * FROM User u LEFT JOIN User_Role ur ON u.id = ur.user_id WHERE ur.role_id = 3;