title: Get ordered list of parent-children in order in single query (MySQL)
body: <p>I have a table called <code>comments</code>.   There are three columns here that are relevant:</p>
  
  <p><code>id, parent_id, create_date</code>.</p>
  
  <p>The parent comments have a <code>parent_id</code> of 0 by default.  Each child has a <code>parent_id</code> of the parent's <code>id</code>. (Obvious stuff thus far)</p>
  
  <p>I am looking for a single SQL query that will order it like this:</p>
  
  <ul>
  <li>First, by the parent's <code>create_date DESC</code></li>
  <li>Second, each child underneath the parent (if a child exists), by <code>create_date DESC</code></li>
  </ul>
  
  <p>An example:</p>
  
  <ol>
  <li>Parent Comment, 1 day ago 
  
  <ol>
  <li>Newest Child comment 1 hour ago</li>
  <li>Second Newest Child comment 3 hours ago</li>
  </ol></li>
  <li>Parent Comment, 3 days ago
  
  <ol>
  <li>First Child Comment, 1 hour ago</li>
  </ol></li>
  </ol>
  
  <p>Is this possible to do in a single query?  Currently I am I am using php nested loops and this is very inefficient.</p>