title: Ordering by a column/attribute of a Left Outer Joined table/association
body: <p>I would like to order records by <code>created_at</code> of a <code>has_many</code> association and come up to the following raw MySQL query (note: <code>articles_author_associations</code> and <code>article_associations</code>):</p>
  
  <pre><code>SELECT 
    DISTINCT `articles`.* 
    FROM `articles` 
  INNER JOIN `articles_author_associations` 
    ON `articles`.`id` = `articles_author_associations`.`article_id`
  LEFT OUTER JOIN `article_associations` 
    ON `article_associations`.`article_id` = `articles`.`id` 
    AND `article_associations`.`author_id` = 2 
  WHERE `articles_author_associations`.`author_id` = 2  
  ORDER BY `article_associations`.`created_at` DESC 
  LIMIT 100
  </code></pre>
  
  <p>The above query returns articles that are not ordered by <code>created_at</code> on the <code>LEFT OUTER JOIN</code> association (the <code>article_associations</code> table).</p>
  
  <p>My question: why? what am I doing wrong?</p>