SQL

<?php
/**
 * Debugging using the database connection.
 */
/** @var \Drupal\Core\Database\Connection */
$connection = \Drupal::service('database');
$query = $connection->select('node', 'node');
$query->fields('node', ['nid'])
  ->condition('node.type', 'page')
  
// Debug.
dump($query->__toString());