SELECT reponse_texte,sujet_id,sujet_titre,studentd.forum_sujet.id_user,date_derniere_reponse AS date,id_dernier_user AS user_id, visite, table_1.login AS auteur
FROM studentd.forum_sujet

LEFT JOIN utilisateurs.user as table_1 ON (table_1.id=studentd.forum_sujet.id_user)
LEFT JOIN studentd.forum_reponse ON (id_sujet=sujet_id)
WHERE id_forum='5'
GROUP BY sujet_titre
ORDER BY studentd.forum_reponse.reponse_date DESC

SELECT command denied to user 'studentd'@'localhost' for table 'user'

Dans la fonction :