SET GLOBAL event_scheduler = ON;
delimiter $$
drop event if exists e_wom_stat;
create event e_wom_stat
on schedule 
EVERY 1 day
 STARTS '2013-01-01 03:00:00'
ON COMPLETION  PRESERVE ENABLE
do
begin
  delete from t_wom_random_num where time<(CURRENT_TIMESTAMP()+INTERVAL -25 MINUTE);
end $$
delimiter ;