DELETE
FROM
    ORDERS
WHERE
    order_date IN(
    SELECT
        order_date
    FROM
        orders AS ord
    LEFT JOIN
        ORDERS_DTL AS dtl
    ON
        ord.order_no = dtl.order_no
    WHERE
        order_date BETWEEN '2010-01-01' AND '2010-12-31'
        );
DELETE
FROM
    ORDERS_dtl
WHERE
    order_no IN(
    SELECT
        dtl.order_no
    FROM
        orders AS ord
    LEFT JOIN
        ORDERS_DTL AS dtl
    ON
        ord.order_no = dtl.order_no
    WHERE
        order_date BETWEEN '2010-01-01' AND '2010-12-31'
        );