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 ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31');

DELETE FROM ORDERS
WHERE ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31';