Changing SQL JOIN type via PHP in Views
You can use query alter will help you out 

function custom_views_query_alter(&amp;$view, &amp;$query) {
    if($view-&gt;name == "tag_cloud"){
        print_r($query);// before modifying the query.
        $query-&gt;table_queue['taxonomy_index']['join']-&gt;type = "LEFT OUTER JOIN";
        //sample field change where  ever you want 
        print_r($query);// after modifying the query .
    }
}


hope this helps