Ways to select nodes from Drupal 7

drupal7_delete_expired_content_v1.php

<?php
error_reporting(0);
ini_set('display_errors', 'Off');
ini_set('display_startup_errors', 'Off');

//Bootstrap Drupal
chdir(getcwd() . '/../');
define('DRUPAL_ROOT', getcwd());
require_once(DRUPAL_ROOT . '/includes/bootstrap.inc');
drupal_override_server_variables();
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

$result = db_query('SELECT n.nid, n.title FROM {node} n, {field_revision_field_schedule} s WHERE n.nid = s.entity_id  AND s.field_schedule_value2 <= :now', array(':now' => date('Y-m-d H:m:s')));
foreach ($result as $record) {
  echo "Deleting nid: " . $record->nid . " " . $record->title;
  node_delete($nid);
}

drupal7_delete_expired_content_v2.php

<?php
error_reporting(0);
ini_set('display_errors', 'Off');
ini_set('display_startup_errors', 'Off');

//Bootstrap Drupal
chdir(getcwd() . '/../');
define('DRUPAL_ROOT', getcwd());
require_once(DRUPAL_ROOT . '/includes/bootstrap.inc');
drupal_override_server_variables();
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

$query = db_select('node','n');
$query->join('field_revision_field_schedule', 's', 'n.nid = s.entity_id');
$nodes = $query->fields('n',array('nid', 'title'))
              ->condition('s.field_schedule_value2', date('Y-m-d H:m:s'),'<=')
              ->execute()
              ->fetchAll(); 

foreach ($nodes as $node) {
  echo "Deleting nid: " . $node->nid . " " . $node->title;
  node_delete($nid);
}

drupal7_delete_expired_content_v3.php

<?php
error_reporting(0);
ini_set('display_errors', 'Off');
ini_set('display_startup_errors', 'Off');

//Bootstrap Drupal
chdir(getcwd() . '/../');
define('DRUPAL_ROOT', getcwd());
require_once(DRUPAL_ROOT . '/includes/bootstrap.inc');
drupal_override_server_variables();
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

$query = db_select('node','n');
$query->join('field_revision_field_schedule', 's', 'n.nid = s.entity_id');
$query->fields('n',array('nid', 'title'));
$query->condition('s.field_schedule_value2', date('Y-m-d H:m:s'),'<=');
$nodes2 = $query->execute()->fetchAll(); 

foreach ($nodes2 as $node2) {
  echo "Deleting nid: " . $node2->nid . " " . $node2->title;
  node_delete($nid);
}

drupal7_delete_expired_content_v4.php

<?php
error_reporting(0);
ini_set('display_errors', 'Off');
ini_set('display_startup_errors', 'Off');

//Bootstrap Drupal
chdir(getcwd() . '/../');
define('DRUPAL_ROOT', getcwd());
require_once(DRUPAL_ROOT . '/includes/bootstrap.inc');
drupal_override_server_variables();
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'node')
  ->propertyCondition('type', 'alert')
  ->propertyCondition('status', NODE_PUBLISHED)
  ->fieldCondition('field_schedule', 'value2', date('Y-m-d H:i:s'), '<=')
  ->range(0, 10)
  ->addMetaData('account', user_load(1));

$result = $query->execute();

if (isset($result['node'])) {
  $nids = array_keys($result['node']);
  foreach ($nids as $nid) {
    node_delete($nid);
  }
}