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 between '2010-01-01' and '2010-12-31';