query('INSERT INTO '.$wpdb->usermeta.'(user_id, meta_key, meta_value) SELECT uu.ID, "_um_last_login", uu.user_registered FROM '.$wpdb->users.' AS uu WHERE uu.ID NOT IN( SELECT user_id FROM '.$wpdb->usermeta.' WHERE meta_key = "_um_last_login" GROUP BY user_id )' ); ?>