如果要每30秒执行以下语句
update userinfo set endtime = now() WHERE id = '';
可以给MySQL建个定时任务，具体如下：
delimiter // /* 设定语句终结符为 //，因存储过程语句用;结束 */
一、查看event是否开启
show variables like '%sche%';
开启event_scheduler
set global event_scheduler =1;
二、创建存储过程test
CREATE PROCEDURE test ()
BEGIN
update userinfo set endtime = now() where id = '';
END;
三、创建event e_test
create event if not exists e_test
on schedule every 30 second
on completion preserve
do call test();
每隔30秒将执行存储过程test
关闭事件任务
alter event e_test OFF COMPLETION PRESERVE DISABLE;
开启事件任务
alter event e_test ON COMPLETION PRESERVE ENABLE;