好的，所以我有一个图书馆风格的数据库，我想获取所有已售罄的书籍的名称。如果所有副本都已出租，则该书被视为已售罄。到目前为止我的查询是：
SELECT Book.Title, Physical_book.book_available AS Available
FROM Book
JOIN Physical_book ON Book.book_id = Physical_Book.book_id
WHERE Physical_book.book_available = 'n';
我的 Physical_Media 表具有 book_available 属性，它告诉您该书是否可用 N 或 Y。在此表中，如果有多个副本，则重复书籍。意思是，如果这本书是，Title One那么我为Title One All 有三个二，并且 Book_ID 相同2。在这三本书中，有两本标有n，另一本标有y。从技术上讲，我想要的是，这个查询只提取那些所有书籍都售罄的人。由于它返回的结果Title ONe显然不能正常工作。有任何想法吗？
表格示例
/* Physical_Book Table */
INSERT INTO Physical_Book (Physical_ID, Book_ID, Book_available)
VALUES (1,1,'y');
INSERT INTO Physical_Book (Physical_ID, Book_ID, Book_available)
VALUES (2,1,'n');
INSERT INTO Physical_Book (Physical_ID, Book_ID, Book_available)
VALUES (3,1,'n');
/*Book Table*/
INSERT INTO Book (Book_ID, author_id, genre_id, title, copyright)
VALUES (1, Tammy, Horror, Book One, 1999)
使用 JW 查询
SELECT Book.Title, Physical_book.book_available AS Available
FROM Book
JOIN Physical_book ON Book.book_id = Physical_Book.book_id
Group BY Book.title, Physical_book.book_available
HAVING COUNT (*) = COUNT (CASE WHEN book_available = 'n' THEN 1 END);