title: Select query with Datetime? and Datetime doesn't work!
body: <p>Here what I would like to do:</p>
  
  <pre><code>var groups = 
    from g in Group.All() 
    where g.FirstDay &lt; startDate &amp;&amp; (g.LastDay == null || g.LastDay &gt;= startDate)
    select g;
  </code></pre>
  
  <p>FirstDate is a dateTime and LastDate is a nullable datetime. I'm getting an "System.InvalidOperationException: The operators of the 'LessThan' do not correspond with parameters from the method 'op_LessThan'."</p>
  
  <p>This query works with small modifications (and completely different results!) like:</p>
  
  <pre><code>var groups = 
    from g in Group.All() 
    where g.LastDay == null &amp;&amp; g.FirstDay &lt; startDate 
    select g;
  
  var groups = 
    from g in Group.All() 
    where (g.LastDay &gt;= startDate || g.LastDay == null)
    select g;
  </code></pre>
  
  <p>I already changed the order of the expressions, but it do not change the results... </p>
  
  <p>Any ideas?!</p>
  
  <p>Thanks!!! I am getting crazy with this small query!</p>