Drupal table with pager from db_select()

drupal_table_pager.php

<?php
/**
 * Display point award report.
 *
 * Generates a list of awarded points.
 *
 * @return array $content
 */
function game_report_page_points() {
  // For some mysterious reason only parts of the db_select API is chainable.
  // Which means that sometimes you have to split it up like I've done below.
  $query = db_select('game_points', 'p')
    ->orderBy('timestamp', 'DESC') // Default sort, not reflected in table. :/
    ->extend('PagerDefault') // Automagical pager
    ->limit(50); // Items per page
  $query->join('users', 'u', 'p.uid = u.uid');

  $query->fields('p', array(
      'id',
      'points',
      'point_name',
      'point_category',
      'timestamp',
      'meta',
    ));
  $query->fields('u', array('name'));

  $result = $query->execute()->fetchAllAssoc('id');

  $render = array(
    'table' => array(
      '#theme' => 'table',
      '#header' => array(
        'id' => array('data' => t('ID'), 'field' => 'id'),
        'points' => array('data' => t('Points'), 'field' => 'points'),
        'point_name' => array('data' => t('Type'), 'field' => 'point_name'),
        'point_category' => array('data' => t('Category'), 'field' => 'point_category'),
        'timestamp' => array('data' => t('Date'), 'field' => 'timestamp'),
        'meta' => array('data' => t('Meta'), 'field' => 'meta'),
        'name' => array('data' => t('User'), 'field' => 'name'),
      ),
      '#rows' => array_map(function ($row) {
        return (array)$row;
      }, $result),
      '#sticky' => TRUE,
      '#empty' => t('No points recorded yet.'),
    ),
    'pager' => array(
      '#theme' => 'pager',
    ),
  );

  _game_preprocess_report($render);

  return $render;
}

/**
 * Preproccsing of report tables.
 *
 * @param array $report
 *
 * @return void
 */
function _game_preprocess_report(&$report) {
  // Format dates, can someone tell me how to do this directly in the
  // query?
  foreach ($report['table']['#rows'] as $key => $row) {
    $time = $row['timestamp'];
    $row['timestamp'] = date('Y-m-d H:i:s', $time);
    $report['table']['#rows'][$key] = $row;
  }
}

Seems like the table won't sort. So I guess the documentation is kinda wrong. Hmm.

About formatting dates in the query:

$entries = $query->execute()->fetchAll(PDO::FETCH_ASSOC);

  if (!empty($entries)) {
    $rows = array();
    foreach ($entries as $entry) {
      $entry['timestamp'] = format_date($entry['timestamp']);
      // Sanitize the data before handing it off to the theme layer.
      $rows[] = array_map('check_plain', $entry);
    }

    // Make a table for them.
    $header = array(t('Id'), t('Message'), t('Time'));
    $output = theme('table', array('header' => $header, 'rows' => $rows));
    $output .= theme('pager', array('tags' => array()));
  }

how do i print the table