Use MySQL to generate a random password

Use MySQL to generate a random password.
DELIMITER $$

CREATE
    FUNCTION `t_girl`.`func_rand_string`(f_num tinyint unsigned,f_type tinyint unsigned)
    RETURNS varchar(32)
    BEGIN
      -- Translate the number to letter.
      -- No 1 stands for string only.
      -- No 2 stands for number only.
      -- No 3 stands for combination of the above.
      declare i int unsigned default 0;
      declare v_result varchar(255) default '';
      while i < f_num do
        if f_type = 1 then
          set v_result = concat(v_result,char(97+ceil(rand()*25)));
        elseif f_type=2 then
          set v_result = concat(v_result,char(48+ceil(rand()*9)));
        elseif f_type=3 then
          set v_result = concat(v_result,substring(replace(uuid(),'-',''),i+1,1));
        end if;
        set i = i + 1;
      end while;
      return v_result;

    END$$

DELIMITER ;

Call method example:
Select func_rand_string (12, 3 );