PDO::lastInsertID 返回 0

PDO::lastInsertID returning 0

在阅读并尝试了关于该主题的几乎所有答案后,lastInsertId 仍然 returns 0。 我想我可能忽略了一些非常明显的东西,但似乎找不到什么。

这是我的代码:

public function create($ordertype, $userid, $travel, $distance, $time, $description, $lineids, $amounts, $descriptions, $prices, $orderid = null) {
    try {

        $stmt = $this->db->prepare("INSERT INTO workorder(orderid, userid, ordertype, travel, description, distance, totaltime) 
                                    VALUES(:orderid, :userid, :ordertype, :travel, :description, :distance, :totaltime)
                                    ON DUPLICATE KEY UPDATE userid=:userid, ordertype=:ordertype, travel=:travel, description=:description,
                                    distance=:distance, totaltime=:totaltime");

        $stmt->bindparam(":orderid", $orderid);
        $stmt->bindparam(":userid", $userid);
        $stmt->bindparam(":ordertype", $ordertype);
        $stmt->bindparam(":travel", $travel);
        $stmt->bindparam(":description", $description);
        $stmt->bindparam(":distance", $distance);
        $stmt->bindparam(":totaltime", $time);
        $stmt->execute();
        $workorderid = $this->db->lastInsertId();
        echo $workorderid;
        exit();

        return $stmt;

        save_lines($workorderid, $lineids, $amounts, $descriptions, $prices);
    } catch(PDOException $e) {
        echo $e->getMessage();
    }
}

这很明显... 我忘了检查记录是否已经存在。如果我不更改记录(工作单)中的任何内容,SQL 查询将不会执行任何操作,并且 lastInsertId 返回 0

我更新的代码(首先检查 orderid 的 id):

public function create($ordertype, $userid, $travel, $distance, $time, $description, $lineids, $amounts, $descriptions, $prices, $orderid = null) {
        try {
            $stmt = $this->db->prepare("INSERT INTO workorder(orderid, userid, ordertype, travel, description, distance, totaltime) 
                                        VALUES(:orderid, :userid, :ordertype, :travel, :description, :distance, :totaltime)
                                        ON DUPLICATE KEY UPDATE userid=:userid, ordertype=:ordertype, travel=:travel, description=:description,
                                        distance=:distance, totaltime=:totaltime");

            $stmt->bindparam(":orderid", $orderid);
            $stmt->bindparam(":userid", $userid);
            $stmt->bindparam(":ordertype", $ordertype);
            $stmt->bindparam(":travel", $travel);
            $stmt->bindparam(":description", $description);
            $stmt->bindparam(":distance", $distance);
            $stmt->bindparam(":totaltime", $time);
            $stmt->execute();
            if($orderid == null) {
                $workorderid = $this->db->lastInsertId();
            } else {
                $workorderid = $orderid;
            }
            if($amounts !== '') {
                $this->save_lines($workorderid, $lineids, $amounts, $descriptions, $prices);
            }
        } catch(PDOException $e) {
            echo $e->getMessage();
        }
    }