title: Alias column name to another
body: <p>I've in my code something like that:</p>
  
  <p>TagsController</p>
  
  <pre><code>@tag = Tag.find(id: Tag.root)
  </code></pre>
  
  <p>tag.rb</p>
  
  <pre><code>def self.root
    TagHierarchy.select('ancestor_id').where(generations: 0)  
  end
  </code></pre>
  
  <p>The problem is:</p>
  
  <p><code>Couldn't find Tag with 'id'={:id=&gt;#&lt;ActiveRecord::Relation [#&lt;TagHierarchy ancestor_id: 1&gt;]&gt;}</code></p>
  
  <p>So I need to alias the column name <code>ancestor_id</code> to <code>id</code> but I don't know how to.. </p>