ruby on rails如何從視圖訪問左連接變量

Question

我的索引控制器：

class IndexController < ApplicationController
    def index
        @posts = Post.find(:all, :limit => 10,
                            :joins => "LEFT JOIN `users` ON users.user_id = posts.user_id",
                            :select => "posts.*, users.username",
                            :order => "posts.created_at DESC")
    end
end

如何從視圖訪問users.username？

我試過了

<% @posts.each do |post| %>
    <%= post.username %>
<% end %>

但這似乎不起作用，因為我收到一條空白消息...

編輯：

我必須在LEFT JOIN中使用以下代碼：

:joins => "LEFT JOIN `users` ON posts.user_id = users.id",

Answer 1

嘗試這個 ..

@posts = Post.find(:all, :limit => 10,
                            :joins => "LEFT JOIN `users` ON users.user_id = posts.user_id",
                            :select => "posts.*, users.username as user_name",
                            :order => "posts.created_at DESC")


<% @posts.each do |post| %>
    <%= post.user_name %>
<% end %>

Answer 2

我必須在LEFT JOIN中使用以下代碼：

:joins => "LEFT JOIN `users` ON posts.user_id = users.id",

Answer 3

您的代碼不是MVC友好的。 這是在Rails中更好的方法。

1.您的模型應執行以下查詢：

class User < ActiveRecord::Base
  has_many :posts
end

class Post < ActiveRecord::Base
  belongs_to :user
  scope :last_10, order("created_at desc").limit(10) #or "id desc" which is quicker
end

2.在控制器中調用查詢

class IndexController < ApplicationController
  def index
    @posts = User.find_by_username(the_username).posts.last_10
  end
end

3.然后，您可以做

<% @posts.each do |p| %>
  <%= post.user.username %>
<% end %>