Ugly mysql warning when empty $vids for prerender in content_handler_field_multiple

Looked a bit but didn't see an issue about this, sorry if I missed it.

An ugly mysql message can be produced when $vids ends up being empty
Problem area

 function pre_render($values) {
    // If there are no values to render (displaying a summary, or query returned no results),
    // or if this is not a grouped field, do nothing specific.
    if (isset($this->view->build_info['summary']) || empty($values) || !$this->defer_query) {
      return parent::pre_render($values);
    }

    $field = $this->content_field;
    $db_info = content_database_info($field);
    $options = $this->options;

    // Build the list of vids to retrieve.
    // TODO: try fetching from cache_content first ??
    $vids = array();
    $this->field_values = array();
    foreach ($values as $result) {
      if (isset($result->{$this->field_alias})) {
        $vids[] = $result->{$this->field_alias};
      }
    }

The thing actually producing the mysql error

 " WHERE vid IN (". implode(',', $vids) .')'.        

since $vids is empty the query contains vid IN (), which mysql doesn't like.

I changed to using this instead so I can test for empty vids

 $vids = array();
     foreach ($values as $result) {
      if (isset($result->{$this->field_alias})) {
        $vids[] = $result->{$this->field_alias};
      }
    }
    if (isset($this->view->build_info['summary']) || empty($values) || !$this->defer_query || !$vids) {
      return parent::pre_render($values);
    }

    $field = $this->content_field;
    $db_info = content_database_info($field);
    $options = $this->options;

    // Build the list of vids to retrieve.
    // TODO: try fetching from cache_content first ??

    $this->field_values = array();

My erroring view is a user view with information from content profiles, which don't necessarily exist for some users.