title: user_load by a user profile field?
body: <p>I'm trying to login users by detecting it's facebook user id.
  "profile_fbuid" is a (hidden) profile field that I created to login users with the corresponding facebook user id.
  When a user tries to login with Facebook I detect his/her facebook user id, but when I try to match with corresponding Drupal user this line doesn't work:</p>
  
  <pre><code>    $user_exists = user_load(array('profile_fbuid'=&gt;$fbuserid));
  </code></pre>
  
  <p>I get this error: <strong>user warning: Unknown column 'profile_fbuid'</strong>  </p>
  
  <p>I know what the error means, but I don't know how can I search a user using a user profile field.</p>
  
  <p>Thanks for your help!</p>