delete
from ORDERS_DTL
where ORDER_NO
in (select ORDERS.ORDER_NO
    from ORDERS
    inner join ORDERS_DTL
        on ORDERS.ORDER_NO = ORDERS_DTL.ORDER_NO
    where ORDERS.ORDER_DATE between '2010-01-01' and '2010-12-31')
;
delete
from ORDERS
where ORDER_DATE between '2010-01-01' and '2010-12-31'
;