how to get last inserted id in codeigniter 3 code example

Example 1: return last insert id in codeigniter

$id = $this->db->insert_id();

Example 2: how to get last id in database codeigniter 4

$db = db_connect();
  $query = $db->query("SELECT * FROM users ORDER BY id DESC LIMIT 1");
  $result = $query->getRow();