DELIMITER $$

DROP PROCEDURE IF EXISTS `stw`.`stw_getuser` $$
CREATE` PROCEDURE `stw_getuser`(IN i_user_id INT)
BEGIN
    DECLARE v_flags VARCHAR(255);

    SELECT CONCAT(
              SELECT stw_flag.name
                FROM stw_flag, stw_user_2_flag
                WHERE stw_flag.flag_id = stw_user_2_flag.flag_id
                  AND stw_user_2_flag.user_id = i_user_id)
           INTO v_flags;
    SELECT *, v_flags flags FROM stw_user WHERE user_id = i_user_id;
END $$

DELIMITER ;