Drupal 7: Get base query of a view

helper.php

<?php

  public static function getBaseQuery($view_name, $display_id, $clear_fields = false) {
    $view = views_get_view($view_name)->copy();
    // Set dummy input to avoid fetching input from $_GET.
    $view->exposed_input = array('' => '');
    $view->set_arguments(array());
    $view->set_display($display_id);

    // Make sure the exposed form is not rendered, otherwise we end up in a
    // recursion.
    $display = $view->display_handler;
    $display->has_exposed = false;
    foreach($display->get_handlers('filter') as $handler_id => $handler) {
      if ($handler->can_expose() && $handler->is_exposed()) {
        unset($display->handlers['filter'][$handler_id]);
      }
    }

    $view->pre_execute();
    $view->build($display_id);

    /* @var $query \SelectQuery */
    $query = $view->build_info['query'];
    $query->range();
    if($clear_fields) {
      $fields = &$query->getFields();
      $order  = &$query->getOrderBy();
      $fields = array();
      $order  = array();
    }
    return $query;
  }