title: Entity framework null value in query
body: <p>I'm seeing a strange behavior in an EF query adn I'm wondering why it is happening.
  With the following code I don't get any results:</p>
  
  <pre><code>if (category.Parent == null)
  {
      return Db.EventCategories.Where(c =&gt; c.Parent == category.Parent);
  }
  </code></pre>
  
  <p>But with this code it does return the expected results:</p>
  
  <pre><code>if (category.Parent == null)
  {
      return Db.EventCategories.Where(c =&gt; c.Parent == null);
  }
  </code></pre>
  
  <p>What is the difference? Isn't null always null? or does the EF treats them as different elements when the value is a nullable (Parent is of type int?).</p>