DELETE
FROM
        ORDERS_DTL
WHERE
        ORDER_NO IN (SELECT
                            ORDER_NO
                    FROM
                            ORDERS
                    WHERE
                            ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31');
                            
DELETE
FROM
        ORDERS
WHERE
        ORDER_DATE BWTWEEN '2010-01-01' AND '2010-12-31';