MySQL if语句触发器

Question

我试图让触发器插入的席位值必须小于31，但由于某些原因触发器不起作用..当我尝试其他解决方案时，任何帮助都会很大，但din效果很好

delimiter |

CREATE TRIGGER seats_check BEFORE INSERT ON booked
  FOR EACH ROW
  BEGIN
  if (new.seats_booked <=30)
  THEN INSERT INTO booked set seats_booked= new.seats_booked;
  ELSE
    INSERT INTO booked set seats_booked=0;
  end if;
  END;
|