有两个表:Books
(列出可用的书)和BorrowedBooks
(列出当前借用的书)。我只想检索当前可用(不借用)的书,提供分页和总数。
我将使用Sequelize提供的方法findAndCountAll
,它确实易于使用并且可以完成大部分工作,但无法正常工作。我已经使用findAll
方法尝试了下面的代码,它可以正常工作。
Books.findAll({
where: { '$BorrowedBooks.bookId$': null },
include: [BorrowedBooks]
}).then(...).catch(...);
然后我将方法更改为
findAndCountAll
,以获得元素的总数并提供分页。Books.findAndCountAll({
where: { '$BorrowedBooks.bookId$': null },
include: [BorrowedBooks],
offset: offset,
limit: limit,
distinct: true
}).then(...).catch(...);
此版本产生错误
Unknown column 'BorrowedBooks.bookId' in 'where clause'
。编辑
生成的查询与不起作用的代码段如下:
SELECT
`books`.*,
`borrowedBooks`.`bookId` AS `borrowedBooks.bookId`,
`borrowedBooks`.`userId` AS `borrowedBooks.userId`,
FROM
(SELECT
`books`.`id`,
`books`.`title`,
`books`.`author`,
`books`.`isbn`
FROM
`books` AS books`
WHERE
(SELECT
`bookId`
FROM
`borrowedBooks`
WHERE
(`borrowedBooks`.`bookId` = `books`.`id`
AND `borrowedBooks`.`bookId` IS NULL)
LIMIT 1) IS NOT NULL
LIMIT 0 , 10) AS `books`
INNER JOIN
`borrowedBooks` ON `books`.`id` = `borrowedBooks`.`bookId`
AND `borrowedBooks`.`bookId` IS NULL;
如果我直接写下查询,我将执行以下操作:
SELECT * FROM `books`
LEFT OUTER JOIN `borrowedBooks` ON `books`.`id` = `borrowedBooks`.`bookId`
WHERE `borrowedBooks`.`bookId` IS NULL
我认为该错误是由于Sequelize使用的INNER JOIN。
最佳答案
使用正确的语法包括
Books.findAll({
include: [{
model: BorrowedBooks,
where: {
bookId: null
}
}],
offset: offset,
limit: limit,
distinct: true
}).then(...).catch(...);