題組內容
二、假設現有如下點歌紀錄的關聯式資料庫,請使用 SQL 回答相關的子問題。(每小題 5 分,共 20 分) Publisher(nation, company_ ID, name) PK: nation+company_ID
Song(song _ ID, name, language, type, publish_year, nation, publisher_ID)
PK: song_ID
FK: nation+publisher_ID ref. Publisher(nation+company_ID)
Member(mobile, nickname, gender) PK: mobile
OnDemand_Record(member_ ID, song _ ID, date_time)
PK: (member_ID, song_ID, date_time)
FK: member_ID ref. Member(mobile)
FK: song_ID ref. Song(song_ID)
註:欄位名稱如相同或顯示非欄位名稱,請使用 Alias 重新命名顯示的欄位
(三)請列出 2024/02/14 的點播歌曲,結果請依歌曲類型及會員性別分類顯示相關的點播次數。
詳解 (共 1 筆)
詳解
SELECT
S.type AS 歌曲類型,
M.gender AS 會員性別,
COUNT(*) AS 點播次數
FROM
OnDemand_Record ODR
JOIN
Song S ON ODR.song_ID = S.song_ID
JOIN
Member M ON ODR.member_ID = M.mobile
WHERE
DATE(ODR.date_time) = '2024-02-14'
GROUP BY
S.type, M.gender;
S.type AS 歌曲類型,
M.gender AS 會員性別,
COUNT(*) AS 點播次數
FROM
OnDemand_Record ODR
JOIN
Song S ON ODR.song_ID = S.song_ID
JOIN
Member M ON ODR.member_ID = M.mobile
WHERE
DATE(ODR.date_time) = '2024-02-14'
GROUP BY
S.type, M.gender;