-- 受注データ明細を先に削除
DELETE FROM ORDERS_DTL
WHERE ORDER_NO IN (
    SELECT ORDER_NO
    FROM ORDERS
    WHERE ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31'
);

-- 受注データを削除
DELETE FROM ORDERS
WHERE ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31';