title: How to sort solr results by foreign id field
body: <p>I have documents with the following fields:  </p>
  
  <pre><code>id
  name
  parent
  color
  </code></pre>
  
  <p>The parent field is an ID of another document.<br>
  I want to select all documents where the color is red and sort the results by the name of the parent.<br>
  Can it be done in solr?</p>