mysql中把数字转换为大写

DELIMITER $$

CREATE FUNCTION `num_to_cn`(n INT) RETURNS VARCHAR(255) CHARSET utf8
BEGIN
    DECLARE units VARCHAR(20) DEFAULT '拾佰仟万拾佰仟亿拾佰仟';
    DECLARE nums VARCHAR(20) DEFAULT '零壹贰叁肆伍陆柒捌玖';
    DECLARE result VARCHAR(255) DEFAULT '';
    DECLARE numStr VARCHAR(20) DEFAULT LPAD(n, 12, '0');
    DECLARE i INT DEFAULT 12;
    
    WHILE i > 0 DO
        SET result = CONCAT(result, SUBSTRING(nums, SUBSTRING(numStr, i, 1) + 1, 1), SUBSTRING(units, i, 1));
        SET i = i - 1;
    END WHILE;
    
    -- 去除多余的“零”
    SET result = REPLACE(result, '零零', '零');
    SET result = REPLACE(result, '零佰', '零');
    SET result = REPLACE(result, '零仟', '零');
    SET result = REPLACE(result, '零拾', '零');
    SET result = REPLACE(result, '零万', '万');
    SET result = REPLACE(result, '零亿', '亿');
    SET result = REPLACE(result, '亿万', '亿');
    
    -- 去除开头的“零”
    IF SUBSTRING(result, 1, 1) = '零' THEN
        SET result = SUBSTRING(result, 2);
    END IF;
    
    RETURN result;
END$$

DELIMITER ;

SELECT num_to_cn(123456789) AS '大写金额';