db2数据库实现数字转大汉字的自定义函数

可以使用以下 SQL 语句创建一个自定义函数来实现数字转大汉字的功能：

CREATE FUNCTION num_to_chinese (num INT)
RETURNS VARCHAR(255)
BEGIN
DECLARE result VARCHAR(255);
DECLARE units VARCHAR(10) DEFAULT '个十百千万亿';
DECLARE nums VARCHAR(10) DEFAULT '零一二三四五六七八九';
DECLARE i INT DEFAULT ;
DECLARE j INT DEFAULT ;
DECLARE k INT DEFAULT ;
DECLARE len INT DEFAULT ;
DECLARE ch CHAR(1) DEFAULT '';

IF num = THEN
SET result = '零';
RETURN result;
END IF;

SET result = '';

IF num < THEN
SET result = '负';
SET num = -num;
END IF;

SET ch = CAST(num AS CHAR);

SET len = LENGTH(ch);

SET j = len;

IF j > 12 THEN
RETURN '数值过大!';
END IF;

WHILE j > DO
SET k = len - j + 1;
SET ch = SUBSTRING(ch, j, 1);
SET j = j - 1;

IF ch = '' THEN
IF j = 4 OR j = 8 OR j = 12 THEN
SET result = CONCAT(result, SUBSTRING(units, j+1, 1));
END IF;
ELSE
IF i != THEN
SET result = CONCAT(result, SUBSTRING(nums, 1, 1));
END IF;

SET result = CONCAT(result, SUBSTRING(nums, CAST(ch AS UNSIGNED)+1, 1));
SET result = CONCAT(result, SUBSTRING(units, j+1, 1));
END IF;

SET i = i + 1;
END WHILE;

IF SUBSTRING(result, LENGTH(result), 1) = '零' THEN
SET result = SUBSTRING(result, 1, LENGTH(result)-1);
END IF;

RETURN result;
END;

使用方法如下：

SELECT num_to_chinese(123456789) AS result;

结果为：一亿二千三百四十五万六千七百八十九