mysql存储过程中游标遍历的方法：
create definer=`root`@`%` procedure `updstatus`()
begin
declare starttime datetime;
declare endtime datetime;
declare curtime datetime;
declare id varchar(36);
declare estatus varchar(4);
-- 遍历数据结束标志
declare done int default false;
-- 游标
declare examids cursor for select exam_id from t_exam where exam_status = 1 or exam_status = 2;
-- 将结束标志绑定到游标
declare continue handler for not found set done = true;
open examids;
-- 遍历
read_loop: loop
-- 取值 取多个字段
fetch next from examids into id;
if done then
leave read_loop;
end if;
select exam_status into estatus from t_exam where exam_id = id ;
if estatus =1 then
select now() into curtime;
select exam_start_time into starttime from t_exam where exam_id = id ;
select exam_end_time into endtime from t_exam where exam_id = id ;
if curtime >= starttime and endtime > curtime then
update t_exam set exam_status = 2 where exam_id = id;
elseif curtime >= endtime then
update t_exam set exam_status = 3 where exam_id = id;
end if;
else
select now() into curtime;
select exam_end_time into endtime from t_exam where exam_id = id ;
if curtime >= endtime then
update t_exam set exam_status = 3 where exam_id = id;
end if;
end if;
end loop;
close examids;
end
