申論題

SELECT M.name AS "鐵粉姓名"
FROM Member M
JOIN Buy B ON M.mId = B.mId
JOIN Author A ON B.pNo = A.pNo
WHERE A.name = '達文西'
GROUP BY M.mId, M.name
HAVING COUNT(DISTINCT B.pNo) = (
    SELECT COUNT(DISTINCT P.pNo)
    FROM Author A
    JOIN Product P ON A.pNo = P.pNo
    WHERE A.name = '達文西'
);