Rails ActiveRecord:查找除当前用户之外的所有用户

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我觉得这应该很简单，但我的大脑正在短路.如果我有一个代表当前用户的对象，并且想查询除当前用户之外的所有用户，我该怎么做，考虑到当前用户有时可以是 nil?

I feel this should be very simple but my brain is short-circuiting on it. If I have an object representing the current user, and want to query for all users except the current user, how can I do this, taking into account that the current user can sometimes be nil?

这就是我现在正在做的:

This is what I am doing right now:

def index @users = User.all @users.delete current_user end

我不喜欢的是我正在对查询结果进行后处理.除了感觉有点不对之外，如果我将查询转换为使用 will_paginate 运行，我认为这不会很好地工作.有关如何通过查询执行此操作的任何建议?谢谢.

What I don't like is that I am doing post-processing on the query result. Besides feeling a little wrong, I don't think this will work nicely if I convert the query over to be run with will_paginate. Any suggestions for how to do this with a query? Thanks.

推荐答案

可以在 Rails 4 及更高版本中执行以下操作:

It is possible to do the following in Rails 4 and up:

User.where.not(id: id)

你可以把它包装在一个很好的范围内.

You can wrap it in a nice scope.

scope :all_except, ->(user) { where.not(id: user) } @users = User.all_except(current_user)

或者，如果您愿意，也可以使用类方法:

Or use a class method if you prefer:

def self.all_except(user) where.not(id: user) end

这两种方法都将返回一个 AR 关系对象.这意味着您可以链接方法调用:

Both methods will return an AR relation object. This means you can chain method calls:

@users = User.all_except(current_user).paginate

您可以排除任意数量的用户，因为 where() 也接受一个数组.

You can exclude any number of users because where() also accepts an array.

@users = User.all_except([1,2,3])

例如:

@users = User.all_except(User.unverified)

甚至通过其他关联:

class Post < ActiveRecord::Base has_many :comments has_many :commenters, -> { uniq }, through: :comments end @commenters = @postmenters.all_except(@post.author)

请参阅API文档<中的where.not()/a>.