drop trigger if EXISTS addchecking; create trigger addchecking after update on ws_device_runing for each row begin if(old.updtime!=new.updtime) then insert into ws_device_checking(partid,devid,itemid,runstate,checked,addtime) values(new.partid,new.devid,new.itemid,new.runstate,0,UNIX_TIMESTAMP()); end if; end;