MySQL random password generation code

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 ; 

select func_rand_string(12,3);