SQL error: 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 is_original = 1 AND DATE_FORMAT(start_dt_est, '%Y-%m-' at line 2

Original query: SELECT * FROM contest WHERE period_id IN (SELECT period_id FROM period WHERE season_id = 6 AND period_number = ) AND is_original = 1 AND DATE_FORMAT(start_dt_est, '%Y-%m-%d') <= DATE_FORMAT(NOW(), '%Y-%m-%d')