MySQL PHP PDO准备的更新语句，不更新数据库

Question

我的PHP PDO Prepared语句不会更新数据库。我检查了绑定参数是否具有正确的数据，但是仍然无法更新数据库。

我已经在论坛上搜索了一些想法，但似乎都没有用：（

非常感谢您的帮助！

谢谢

$transactiondate = date("Y-m-d");
$transactiontime = date("H:i:s");
$totalsale = $_POST['totalsale_complete'];
$transactionstatus = 'Completed';
$transactionid = $_POST['currenttransactionid_complete'];

    try {
        $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);


    // set the PDO error mode to exception
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $stmt = $conn->prepare("UPDATE ticketsales_all
    SET eventdate = :eventdate,
    transactiondate = :transactiondate,
    transactiontime = :transactiontime,
    transactionstatus = :transactionstatus,
    totalsell = :totalsale
    WHERE transactionid = :transactionidnow");

        $stmt->bindParam(':eventdate', $activeeventdate);
        $stmt->bindParam(':transactiondate', $transactiondate);
        $stmt->bindParam(':transactiontime', $transactiontime);
        $stmt->bindParam(':transactionstatus', $transactionstatus);
        $stmt->bindParam(':totalsale', $totalsale);
        $stmt->bindParam(':transactionidnow', $transactionid);
        $stmt->execute();