delete from ORDERS_DTL
where exists
     (
      select 'X'
      from   ORDERS t10
      where  t10.order_no = ORDERS_DTL.order_no
      and    t10.ORDER_DATE between '2010-01-01' and '2010-12-31'
     )
;
delete from ORDERS
WHERE  ORDER_DATE between '2010-01-01' and '2010-12-31'
;