CodeIgniter active record query to return a column value from a single row otherwise a default value

Question

How can I change this CodeIgniter query() call into separate query builder methods?

$q = "SELECT u.token
      FROM user u 
      WHERE u.userid = ?";
$r = $this->db->query($q, [$id]);

$this->db->close();

return count($r->result_object) == 1
    ? $r->row()->token
    : 0;

Answer 1

$query = $this->db
    ->select('u.token')
    ->from('user u')
    ->where('u.userid', $id)
    ->get();

return ($query->num_rows() == 1)    ?   $query->row()->token    :   0;