DELETE ORDERS,ORDERS_DTL
FROM 
 ORDERS as T1
 LEFT JOIN ORDERS_DTL as T2
 ON T1.ORDER_NO = T2.ORDER_NO
WHERE T1.ORDER_DATE >= '2010-01-01'
 AND T1.ORDER_DATE <= '2010-12-31'

-- 2010年1月1日から2010年12月31日