Drupal: Render form including results, but don't duplicate resultset query

Aim is to display a form, with a default resultset on the page, and allow the viewer to filter the results on the page by form submission. This part works.

However: If a default set of results is included, then the initial submissi开发者_JAVA技巧on builds two resultsets for display. Subsequent submissions build only one resultset. Apart from this additional resultset build, it works as intended.

A couple of questions have asked about displaying forms and results on the same page before, and there's a Lullabot article for Drupal5.

Here's the code I'm using currently (available on Github @ example_formandresults.module)

<?php

/**
 * Implementation of hook_menu().
 */
function example_formandresults_menu() {
  $items['example_formandresults'] = array(
    'title' => 'Example: Form and Results',
    'description' => 'Show a form and its results on the same page.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array( 'example_formandresults_form' ),
    'access arguments' => array('access content'),
    'type' => MENU_NORMAL_ITEM,
  ) ;
  return $items ;
}

/**
 * Form builder function.
 */
function example_formandresults_form(&$form_state = NULL) {
  /* Setting rebuild to true should prevent the results table being built twice. */
  $form_state['rebuild'] = TRUE ;

  if ( is_null($form_state) || !$form_state['submitted'] ) {
    drupal_set_message('Form has not been submitted.');
    /* set default 'since' value to unix timestamp of "one week ago" */
    $form_state['storage']['since'] = strtotime('-1 week');
  }
  else {
    $form_state['storage']['since'] = strtotime($form_state['values']['since']['year'] .'-'. $form_state['values']['since']['month'] .'-'. $form_state['values']['since']['day']);
  }

  $form['since'] = array(
    '#type' => 'date',
    '#title' => t('Since'),
    '#description' => t('Show entries since the selected date.'),
    '#default_value' => array(
      'month' => format_date($form_state['storage']['since'], 'custom', 'n'),
      'day'   => format_date($form_state['storage']['since'], 'custom', 'j'),
      'year'  => format_date($form_state['storage']['since'], 'custom', 'Y'),
    ),
    '#weight' => 5,
  ) ;

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Submit',
    '#weight' => 10,
  ) ;

  if ( $form_state['submitted'] ) {
    $form['results'] = array(
      '#value' => example_formandresults_resultstable($form_state),
      '#type' => 'markup',
      '#weight' => 10, // bottom of form
    ) ;
  }

  return $form ;
}

/**
 * Build results table.
 */
function example_formandresults_resultstable($form_state) {
  drupal_set_message('Building results table.', 'status', TRUE);
  dpm($form_state, 'form state');
  $sql = "SELECT uid FROM {users} WHERE login >= %d ORDER BY login";
  $qry = db_query($sql, $form_state['storage']['since']);
  while ( $uid = db_result($qry) ) {
    $account = user_load($uid);
    /* there are plenty of good examples on how to theme tables in
     * forms; this isn't one. 
     */
    $rows[] = array(
      $account->name,
      format_date($account->login),
    ) ;
  }
  // dpm($rows, 'rows');
  $headers = array( 'Name', 'Last Login' );
  $result = t("<h3>Accounts logged in since: %since</h3>", array('%since' => format_date($form_state['storage']['since']))) ;
  $result .= theme('table', $header, $rows) ;
  return $result ;
}

Try checking for count($form_state['values']) or even $form_state['post'] to tell if the form has been submitted.