title: Entity Framework Filter by grandchildren entities
body: <p>If I have the following tables:
  <br><code>Parent</code>: has <code>ParentId</code>
  <br><code>Child</code>: has <code>ChildId</code> and <code>ParentId</code>
  <br><code>Grandchild</code>: has <code>GrandchildId</code>, <code>ChildId</code> and <code>Quantity</code></p>
  
  <p>Whats the best approach to retrieve a list of Parents where they have a grandchild with quantity greater than 10 (for example)?</p>
  
  <p>I played with linq to entity, generating something like:</p>
  
  <pre><code>context.Parent.Includes("Children").Include("GrandChildren").Where( ... )
  </code></pre>
  
  <p>But wasn't sure about the syntax, and I wonder about performance- do the includes load up all objects?  What's the best way to accomplish this?</p>