mysql随机数

1DELIMITER $$
2CREATE DEFINER = `root` @`localhost` FUNCTION `func_range_string_mod` ( f_num INT UNSIGNED -- Total strings.
3) RETURNS VARCHAR ( 200 ) CHARSET latin1 BEGIN
4DECLARE
5    i INT UNSIGNED DEFAULT 0;
6DECLARE
7    v_result VARCHAR ( 200 ) DEFAULT '';
8DECLARE
9    v_dict VARCHAR ( 200 ) DEFAULT '';
10
11SET v_dict = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
12
13SET v_dict = LPAD( v_dict, 200, v_dict );
14WHILE
15        i < f_num DO
16        
17        SET v_result = CONCAT( v_result, SUBSTR( v_dict, CEIL( RAND( ) * 200 ), 1 ) );
18    
19    SET i = i + 1;
20    
21END WHILE;
22RETURN v_result;
23
24END $$DELIMITER;
25
26SELECT func_range_string_mod(6);