将SQL转换为在Flask中运行的带有Join的Sqlalchemy Select

我到处寻找使用类似于我的语法的SQLAlechmy语句的例子,但似乎找不到任何,所以这里是我的问题。

SELECT register.username, rating, reviews 
FROM reviews 
JOIN register ON reviews.user_id = register.id 
JOIN books ON reviews.book_id = books.id

我像so一样在SQLAlchemy语句中使用占位符,并希望继续使用此项目的语法。

books = db.execute("SELECT * FROM books WHERE id = :id", {"id": book_id})

我尝试了几次转换目标SQL语句,但似乎无法正确地使用占位符。这是最近一次失败的尝试。

db.execute("SELECT register.username, rating, reviews FROM reviews JOIN register ON reviews.user_id = :register.id \
    JOIN books ON reviews.book_id = :books.id", {"register.id": register_id}, {"books.id": book_id})

编辑:

为了解决更简单的问题并扩大规模,我将查询更改为以下内容:

db.execute("SELECT register.username, rating, reviews FROM reviews JOIN register ON reviews.user_id = :register.id", {"register.id": register_id}).fetchall()

sqlalchemy.exc.StatementError: (sqlalchemy.exc.InvalidRequestError) A value is required for bind parameter 'register' [SQL: 'SELECT register.username, rating, reviews FROM reviews JOIN register ON reviews.user_id = %(register)s.id'] [parameters: [{'register.id': 7}]]

它想绑住 register ,这是一张桌子。尝试可能的修复方法。