Erreur SQL

Une requête SQL a échouée :
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND t.id_partie = p.id_partie AND (p.action_type="titulaire" OR p.act' at line 5
SELECT t.id_partie FROM championnat_partie t, partie_stats p WHERE t.id_championnat = 511 AND p.id_utilisateur = AND t.id_partie = p.id_partie AND (p.action_type="titulaire" OR p.action_type="entree") GROUP BY t.id_partie