title: join two tables with multiple condition in linq
body: <p>I am new to LinQ and have some issues while executing a Linq statement. Below is the summary of the same.</p>
  
  <p>I have two class objects with same class type, eg: Report r1, Report r2 which has values like month, ID, values. values are different for both objects. eg:</p>
  
  <pre><code>List&lt;Report&gt; r1 = new List&lt;Report&gt;();
  List&lt;Report&gt; r2 = new List&lt;Report&gt;();
  
          r1.Add(new Report { month = 1, ID = 1, a = 5, b = 12 });
          r1.Add(new Report { month = 1, ID = 2, a = 6, b = 13 });
          r1.Add(new Report { month = 2, ID = 1, a = 6, b = 14 });
          r1.Add(new Report { month = 2, ID = 2, a = 8, b = 15 });
          r1.Add(new Report { month = 3, ID = 2, a = 9, b = 16 });
  
  
          r2.Add(new Report { month = 1, ID = 1, a = 5, b = 22 });
          r2.Add(new Report { month = 1, ID = 2, a = 6, b = 23 });
          r2.Add(new Report { month = 2, ID = 1, a = 6, b = 24 });
  
  
          var delreport =
                              from rr1 in r1
                              join rr2 in r2 on new { rr1.month, rr1.ID }
                              equals new { rr2.month, rr2.ID } into result
                              select result;
  </code></pre>
  
  <p>However, I am getting blank result set. I am expecting to get r2 data (a, b values) matching with <strong>month</strong> and <strong>id</strong> of r1 along with r1 data (a, b values).
  hope, my question is clear, request your help.</p>