DROP FUNCTION IF EXISTS `okmFirstNumberPos`;
DELIMITER ;;
CREATE FUNCTION `okmFirstNumberPos` (`instring` varchar(4000)) 
RETURNS int
LANGUAGE SQL
DETERMINISTIC
NO SQL
SQL SECURITY INVOKER
BEGIN
    DECLARE position int;
    DECLARE tmp_position int;
    SET position = 5000;
    SET tmp_position = LOCATE('0', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF; 
    SET tmp_position = LOCATE('1', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('2', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('3', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('4', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('5', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('6', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('7', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('8', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;
    SET tmp_position = LOCATE('9', instring); IF (tmp_position > 0 AND tmp_position < position) THEN SET position = tmp_position; END IF;

    IF (position = 5000) THEN RETURN 0; END IF;
    RETURN position;
END
;;

DROP FUNCTION IF EXISTS `okmNaturalSort`;
DELIMITER ;;
CREATE FUNCTION `okmNaturalSort` (`instring` varchar(4000), `numberLength` int, `sameOrderChars` char(50)) 
RETURNS varchar(4000)
LANGUAGE SQL
DETERMINISTIC
NO SQL
SQL SECURITY INVOKER
BEGIN
    DECLARE sortString varchar(4000);
    DECLARE numStartIndex int;
    DECLARE numEndIndex int;
    DECLARE padLength int;
    DECLARE totalPadLength int;
    DECLARE i int;
    DECLARE sameOrderCharsLen int;

    SET totalPadLength = 0;
    SET instring = TRIM(instring);
    SET sortString = instring;
    SET numStartIndex = okmFirstNumberPos(instring);
    SET numEndIndex = 0;
    SET i = 1;
    SET sameOrderCharsLen = CHAR_LENGTH(sameOrderChars);

    WHILE (i <= sameOrderCharsLen) DO
        SET sortString = REPLACE(sortString, SUBSTRING(sameOrderChars, i, 1), ' ');
        SET i = i + 1;
    END WHILE;

    WHILE (numStartIndex <> 0) DO
        SET numStartIndex = numStartIndex + numEndIndex;
        SET numEndIndex = numStartIndex;

        WHILE (okmFirstNumberPos(SUBSTRING(instring, numEndIndex, 1)) = 1) DO
            SET numEndIndex = numEndIndex + 1;
        END WHILE;

        SET numEndIndex = numEndIndex - 1;

        SET padLength = numberLength - (numEndIndex + 1 - numStartIndex);

        IF padLength < 0 THEN
            SET padLength = 0;
        END IF;

        SET sortString = INSERT(sortString, numStartIndex + totalPadLength, 0, REPEAT('0', padLength));

        SET totalPadLength = totalPadLength + padLength;
        SET numStartIndex = okmFirstNumberPos(RIGHT(instring, CHAR_LENGTH(instring) - numEndIndex));
    END WHILE;

    RETURN sortString;
END
;;
