title: Filter Magento collection but not products, using distinct
body: <p>In my magento store I am trying to retrieve a list of youtube videos from a DB table, some videos are duplicated.</p>
  
  <p>I'm looking to filter videos by using distinct video "value" but can't seam to find any information about using distinct with addFieldToFilter()</p>
  
  <pre><code>// get video collection
  
  $collection = Mage::getModel('video/video')-&gt;getCollection();
  $collection-&gt;addFieldToFilter('provider', 'youtube');
  
  // filter by video value
  
  $collection-&gt;addFieldToFilter('value')-&gt;distinct(true);
  </code></pre>
  
  <p>By removing <code>$collection-&gt;addFieldToFilter('value')-&gt;distinct(true);</code> it works, but retrieves all the videos.</p>