title: how to fetch data from one class to another in orientdb
body: <p>I have created two classes <strong>customer</strong> and <strong>city</strong>. 
  <strong>customer</strong> class contain two properties <em>name</em> and <em>location</em> and <strong>city</strong> class contain <em>id</em> and <em>location</em> .
  I want to perform join operations on these two classes.
  I create a graph relation in orientdb studio and fire a query below</p>
  
  <pre><code>select from customer where city.location='pune'
  </code></pre>
  
  <p>but this query not returning any value,it executed but not returning any field,
  So, this is correct syntax or i am doing wrong in somewhere ..
  please give me solutions.</p>