DELETE 
FROM
    STOCK 
WHERE
    -- BETWEEN句で最終出荷日の範囲指定をおこなう
    LAST_DELIVERY_DATE BETWEEN '2023-01-01' AND '2023-01-31' 
    AND ACTUAL_AMT = 0;
 
DELETE FROM STOCK
WHERE LAST_DELIVERY_DATE BETWEEN '2023-01-01' AND '2023-01-31'
  AND ACTUAL_AMT IS NULL;