What is the differece between my codes when I use cursor to fetch my data with repeat and do while?

Question

I use cursor to fetch my datas.The number of my data is two.But I find that when I use repeat to fetch my data,it always fetch 3 times. And When I use do while,it is right which fetch 2 times.What is the different of thest two ways?How to fixed the first way?

--- The first way:wrong,have two datas but show 3 times
declare v_done tinyint default 0;
declare v_count int default 0;
declare v_id varchar(32);
declare v_result_cur cursor for select distinct(id) from book;
declare continue handler for not found set v_done = 1;
BEGIN
open v_result_cur;
repeat
 fetch v_result_cur into v_id;
 select v_id;  
until v_done end repeat;
close v_result_cur;
END;

The first way is wrong and the second way is right.

 --- The second way:right,have two datas but show 2 times
BEGIN
declare v_done tinyint default 0;
declare v_count int default 0;
declare v_id varchar(32);
declare v_result_cur cursor for select distinct(id) from book;
BEGIN
open v_result_cur;

 dept_loop:WHILE(v_done=0) DO
                 fetch v_result_cur into v_id;
                  select v_id; 
                 IF v_done=1 THEN
                    LEAVE dept_loop;
                 END IF;
END WHILE dept_loop;
close v_result_cur;
END;

Answer 1

Just add a justment before the execute statement.

 open v_result_cur;
 repeat
 fetch v_result_cur into v_id;
 IF NOT v_done THEN
  select v_id; 
 END IF;
until v_done end repeat;
close v_result_cur;