title: Inner join to get those not in table
body: <p>I have two tables in my database. A person and a coach table. The person table contains all the people and if one of the people is a coach his ID will be in the coach table.
  I need to find all the people who are not coaches... yet and post them in a list.
  I have tried:</p>
  
  <pre><code>var query = from es in gr.people
                              join esh in gr.coaches on es.id equals esh.personID
                              where es.id != esh.personID
                              select es;
  </code></pre>
  
  <p>And this:</p>
  
  <pre><code>var query = from es in gr.people
                              join esh in gr.coaches on es.id equals esh.personID
                              where es.id != esh.personID &amp;&amp; es.id.hasValue
                              select es;
  </code></pre>
  
  <p>But the last one doesn't alow the .hasValue. And so far it doesn't work :(
  Can anybody help me or give me a hint??</p>