MySQL - LEFT JOIN
Zwei relationale MySQL-Tabellen miteinander verknüpfen
SELECT A.vorname,B.geburtstag FROM users AS A
LEFT JOIN users_profiles AS B ON A.id=B.id_user
WHERE A.id=2
SELECT A.vorname,B.geburtstag FROM users AS A
LEFT JOIN users_profiles AS B ON A.id=B.id_user
WHERE A.id=2