title: Join doesn't working in LINQ in Devexpress XPO
body: <p>I have used persistance class and used following LINQ query :</p>
  
  <pre><code>XPQuery&lt;Students&gt; objStudentQuery = new XPQuery&lt;Students&gt;(XpoDefault.Session);
  XPQuery&lt;ExamDetails&gt; objExamDetailsQuery = new XPQuery&lt;ExamDetails&gt;(XpoDefault.Session);
  
  var ExamDetails = from exm in objExamDetailsQuery
                            join student in objStudentQuery on exm.StudentId equals student.StudentId
                            select new { student.FirstName, student.LastName, exm.ExamName, exm.Marks, exm.Date };
  </code></pre>
  
  <p>but it throws an error saying. "Specified Method is not Supported"</p>
  
  <p>How can i get data from two table using XPO Persistance Class?</p>
  
  <p>Thanks</p>