Rails 3 ActiveRelation 添加“is null”在加入...我如何阻止它这样做？
我正在尝试我的第一次连接，它生成的 sql 非常奇怪。
我有一个属于用户的收件人。我正在尝试查询用户的所有收件人，这些收件人也未被读取且未被删除：
scope :unread, where(:is_read => false).where(:is_deleted => false)
scope :unread_by_user_id, lambda { |id| unread.joins(:user).merge(User.by_id(id)) }
这是它生成的sql：
SELECT `recipients`.* FROM `recipients` INNER JOIN `users` ON `users`.`id` IS NULL WHERE `recipients`.`is_read` = 0 AND `recipients`.`is_deleted` = 0 AND `users`.`id` = 475
有什么方法可以摆脱“IS NULL”吗？那不应该在那里 :(
我尝试在 google 上搜索，令人惊讶的是 95% 的示例都没有谈论联接。我发现的少数几个联接示例使用了已被弃用的 & 语法与其他东西相比，这方面的文档实际上非常糟糕，无论如何
，当你开发软件 19 年却无法实现这一点时，这绝对不是一个好日子。 sql 连接到单个表:( 我可以手动在 sql 中编写具有 15 个连接的查询，没有问题。我想这就是您在学习新框架时有时要付出的代价。尽管在 Hibernate 中，这并不奇怪：/
I am trying my first join and the sql that it's generating is very odd.
I have a Recipient belongs to a User. I am trying to query all the recipients by a user that are also not read and not deleted:
scope :unread, where(:is_read => false).where(:is_deleted => false)
scope :unread_by_user_id, lambda { |id| unread.joins(:user).merge(User.by_id(id)) }
This is the sql it generates:
SELECT `recipients`.* FROM `recipients` INNER JOIN `users` ON `users`.`id` IS NULL WHERE `recipients`.`is_read` = 0 AND `recipients`.`is_deleted` = 0 AND `users`.`id` = 475
Is there any way I can get rid of the "IS NULL"? That's not supposed to be there :(
I have tried searching google, and it's actually really amazing that 95% of examples out there do not talk about joins. The few examples of joins that I do find use the & syntax that has become depreciated. The documentation for this is actually quite bad compared to other things. Very odd indeed.
Anyway, I can't get this to work. It's definitely not a good day when you've been developing software for 19 years and can't get sql to join on a single table :( I can write queries in sql with 15 joins no problem manually. I guess that's the price you pay sometimes when you go through and learn new frameworks. It's not this weird though in Hibernate :/
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假设您已获取用户：
收件人关联已将收件人限制为该用户。对此有一个单独的范围对我来说没有意义。
--edit
如果您的用户模型定义了
has_many :recipients关联，则此方法有效。Assuming you have your user fetched already:
Recipients association already limits recipients to that user. Having a separate scope for that doesn't make sense to me.
--edit
This works if your User model has
has_many :recipientsassociation defined.