BEGIN
    IF (in_drop_value IS NULL) THEN
        SIGNAL SQLSTATE '02200'
           SET MESSAGE_TEXT = 'Function sys.list_drop: in_drop_value input variable should not be NULL',
               MYSQL_ERRNO = 1138;
    END IF;
    IF (in_list IS NULL OR LENGTH(in_list) = 0) THEN
        RETURN in_list;
    END IF;
    RETURN (SELECT TRIM(BOTH ',' FROM REPLACE(REPLACE(CONCAT(',', in_list), CONCAT(',', in_drop_value), ''), CONCAT(', ', in_drop_value), '')));
END