-- 1. 受注データ明細 (ORDERS_DTL) を削除
DELETE FROM ORDERS_DTL
WHERE ORDER_NO IN (
    SELECT ORDER_NO 
    FROM ORDERS 
    WHERE ORDER_DATE BETWEEN '2010-01-01' AND '2010-12-31'
);

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