MySQL stored procedures and the use of 'Cursor'

Here's an example:

CREATE PROCEDURE `justifyGroupNum`() 
NOT DETERMINISTIC 
SQL SECURITY DEFINER 
COMMENT '' 
BEGIN 
/*how to run:call justifyGroupNum()*/ 
DECLARE p_group_id int; 
declare p_num int; 
declare stopFlag int; 
DECLARE cursor_name CURSOR 
FOR select c_group_id,count(*) as num 
from `t_group_member` 
where c_valid in (3,4) 
group by c_group_id; 
DECLARE CONTINUE HANDLER FOR NOT FOUND set stopFlag=1; 
OPEN cursor_name; 
REPEAT 
FETCH cursor_name INTO p_group_id,p_num; 
begin 
update t_groupinfo set c_member_number=p_num where c_group_id=p_group_id; 
end; 
UNTIL stopFlag = 1 
END REPEAT; 
CLOSE cursor_name; 
END; 

Conclusion:
1. Note that countinue handler: DECLARE CONTINUE HANDLER FOR NOT FOUND set stopFlag=1;
2. Pay attention to the use of REPEAT and UTILE [stop condition] END REPEAT, otherwise it will not circulate;
3. How to RUN, enter and execute: call justifyGroupNum()