title: ISNULL function within select command of formview
body: <p>This is part of my select statement within an formview which works fine till it hits a null value during the update process.</p>
  
  <pre><code> (SELECT TOP 1 F.tel_id FROM TELEPHONE as F where F.tel_type_id = 3 AND F.client_id = @id
   ORDER BY sort_no ) AS faxid
  </code></pre>
  
  <p>so i tried using the ISNULL function in the following way but it throws error. how can it be done?</p>
  
  <pre><code>ISNULL((SELECT TOP 1 F.tel_id FROM TELEPHONE as F where F.tel_type_id = 3 AND F.client_id= @id ORDER BY sort_no ) AS faxid ,0) AS faxid
  </code></pre>