DELIMITER $$

CREATE FUNCTION  `replace_number_to_zh`(original VARCHAR(1000))
RETURNS VARCHAR(1000)
DETERMINISTIC
BEGIN 
 DECLARE temp VARCHAR(1000); 
 DECLARE ch VARCHAR(1); 
 DECLARE i,j INT;
 DECLARE nums VARCHAR(200);
 DECLARE cns VARCHAR(200);
 DECLARE nums_count INT;
 
 SET nums = '0,1,2,3,4,5,6,7,8,9';
 SET cns = '零,一,二,三,四,五,六,七,八,九';
 SET nums_count = CHAR_LENGTH(nums)-CHAR_LENGTH(REPLACE(nums,',','')) + 1; 

 SET i = 1;
 SET temp = '';
 IF original REGEXP '[0-9]' THEN 
  loop_label: LOOP 
   IF i>CHAR_LENGTH(original) THEN
    LEAVE loop_label;  
   END IF;
   SET ch = SUBSTRING(original,i,1);
   IF NOT ch REGEXP '[0-9]' THEN
    IF ch = ' ' THEN
      SET i=i+1;
      ITERATE loop_label;
    END IF;
    SET temp = CONCAT(temp,ch);
   ELSE
    SET j = 1;
    WHILE j <= nums_count DO
      IF ch = SUBSTRING_INDEX(SUBSTRING_INDEX(nums, ',', j),',',-1) THEN
        SET temp = CONCAT(temp,SUBSTRING_INDEX(SUBSTRING_INDEX(cns, ',', j),',',-1));
      END IF;
      SET j=j+1;
    END WHILE;
   END IF;
   SET i=i+1;
  END LOOP;
 ELSE
  SET temp = original;
 END IF;
 RETURN temp;
END$$

DELIMITER ;

说实话，以前真没写过sql函数。这次涉及到，就勉勉强强写了个，记录下便于以后参考。
该函数的功能就是去空格，单个阿拉伯数字换成中文数字。

主要涉及的点就是数组循环、正则匹配。

参考：http://stackoverflow.com/ques…
http://www.cnblogs.com/caicai…
http://stackoverflow.com/ques…
http://www.cnblogs.com/caorui…