A Database Error Occurred

Error Number: 1064

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 'Connor') END WHERE user_id=1' at line 1

UPDATE phpbb_profile_fields_data SET pf_fav_books = CASE pf_fav_books WHEN "" THEN "Flannery O'Connor" ELSE CONCAT(pf_fav_books,', ','Flannery O'Connor') END WHERE user_id=1