Ayuda con JOIN, por favor

[Italico76]

SELECT u.user_firstname,u.user_lastname,s.skill_name
FROM skills s
JOIN user_skill us ON s.skill_id = us.skill_id
JOIN users u ON us.user_id = u.user_id
WHERE u.user_firstname = 'Juan'
AND u.user_lastname = 'Perez'

Ya soy feliz