Filter view by users without a matching record in the related userpoints table
I figured it out:

function MYMODULE_views_query_alter(&amp;$view, $query) {
 if($view-&gt;name = "nameofview") {
     $query-&gt;where[1]['conditions'][] = array('field' =&gt; 'userpoints_total.points', 'operator' =&gt; 'IS NULL',);
    }
}