title: Linq - How to do two select queries?
body: <pre><code>SELECT userid FROM userTable 
  WHERE userid in (select writeuserid FROM boardTable)
  </code></pre>
  
  <p>C# LINQ expressions, how to use a query?</p>
  
  <p>I have been using EF4. 
  userTable, boardTable is connected to the DbContext.</p>