/**
 * Implements hook_views_query_alter().
 */
function internetdevels_views_query_alter(&$view, &$query) {
  if ($view->name == 'view_faq' && $view->current_display == 'page') {
    $arg = arg();
    $tid_key = '';
    foreach ($query->where[1]['conditions'] as $key => $value) {
      if ($value['field'] == 'taxonomy_term_data.tid') {
        $tid_key = $key;
      }
    }

    if (!isset($arg[1])) {
      $condition = 0;
    }
    if (isset($arg[1]) && is_numeric($arg[1])) {
      $condition = $arg[1];
    }

    $parents = db_select('taxonomy_term_data', 'td');
    $parents->join('taxonomy_term_hierarchy', 'th', 'td.tid = th.tid');
    $parents
      ->condition('th.parent', $condition)
      ->condition('td.vid', 1);
    $parents->fields('td', array('tid'));
    $results = $parents->execute();
    $tids = array();
    while ($value = $results->fetchAssoc()) {
      $tids[] = $value['tid'];
    }
    $query->where[1]['conditions'][$tid_key]['field'] = 'taxonomy_term_data.tid';
    $query->where[1]['conditions'][$tid_key]['value'] = array();
    $query->where[1]['conditions'][$tid_key]['operator'] = 'IN';
    $query->where[1]['type'] = 'AND';
    $query->where[1]['conditions'][$tid_key]['value'] = $tids;
  }