title: Find missing months from the result set obtained from query
body: <p>I have a set of results returning from myTable  as below</p>
  
  <pre><code>2011-05-02 00:00:00.000 
  2011-08-01 00:00:00.000
  2011-09-01 00:00:00.000
  2011-10-03 00:00:00.000
  2011-11-01 00:00:00.000
  2011-12-01 00:00:00.000
  </code></pre>
  
  <p>I want to write a query to return 2 since 2 months are missing from the resultset.So that I can raise an error to break the code.</p>
  
  <p>In case the dataset looks like this</p>
  
  <pre><code>        2011-05-02 00:00:00.000
          2011-05-02 00:00:00.000
          2011-05-02 00:00:00.000
          2011-05-02 00:00:00.000          
          2011-08-01 00:00:00.000
          2011-08-01 00:00:00.000 
          2011-08-01 00:00:00.000
          2011-08-01 00:00:00.000
  </code></pre>
  
  <p>Again return 2 since 2 months are missing</p>