DELETE FROM ORDERS_DTL 
    WHERE EXISTS (
        SELECT *
        FROM ORDERS
        WHERE ORDERS.ORDER_NO = ORDERS_DTL.ORDER_NO
            AND ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31'
    )
;
DELETE FROM ORDERS
    WHERE ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31'
;