title: Case insensitive group on multiple columns
body: <p>Is there anyway to do a LINQ2SQL query doing something similar to this:</p>
  
  <pre><code>var result = source.GroupBy(a =&gt; new { a.Column1, a.Column2 });
  </code></pre>
  
  <p>or</p>
  
  <pre><code>var result = from s in source
               group s by new { s.Column1, s.Column2 } into c
               select new { Column1 = c.Key.Column1, Column2 = c.Key.Column2 };
  </code></pre>
  
  <p>but with ignoring the case of the contents of the grouped columns?</p>