query builder join codeigniter 4

public function join_example () { $db = \Config\Database::connect (); $builder = $db-table ('authors AS A'); $builder-select ('B. permainan dop 4 level 299 book_id,B book'); $builder-join ('books AS B', 'A author_id = B author_id'); $builder-where ('A author_id', $author); $query = $builder-get ()-getResult (); return