php - 最后插入 ID = 0

Question

我正在尝试插入我的数据库，它工作正常，但 LastInsertId 总是显示为 0，有什么想法吗？

$stmt = $db->prepare('INSERT INTO players_results (matchweek_id, matchweek, game_id, username, homeresult, awayresult, goals, submit, matchweek_session) Values (:matchweekid, :matchweek, :gameid, :username, :homeresult, :awayresult, :goals, :submit, :matchweeksession)');

          for ($gi = 1; $gi <= 10; $gi++) {
            $stmt->execute(array(
            ':matchweekid' => '1',
            ':matchweek' => 'Matchweek 1',
            ':gameid' => $gi,
            ':username' => $_POST['username'],
            ':homeresult' => NULL,
            ':awayresult' => NULL,
            ':goals' => NULL,
            ':submit' => 'n',
            ':matchweeksession' => 'open'   
          ));
          $id = $db->lastInsertId('member_id');
        }

Answer 1

//改变

$id = $db->lastInsertId();

到

$id = $stmt->lastInsertId();