title: if exists statement in sql to linq
body: <p>What is the linq equivalent of the following statement ?</p>
  
  <pre><code>IF NOT EXISTS(SELECT UserName FROM Users WHERE UserName='michael')
  BEGIN
  INSERT INTO Users (UserName) values ('michael');
  END
  </code></pre>
  
  <p>also can you suggest any sql-to-linq converters? I am currently using LINQPad which does a great job in terms of writing linq code where you can also see the generated sql code however when I click the little linq sign, nothing is displayed.</p>