数据未插入 SQL 我的代码有什么问题？

我一直在关注一个教程，其中包括将数据插入数据库，然后发送电子邮件以确认该帐户确实由电子邮件的同一所有者拥有。这是我正在关注的视频。

https://www.youtube.com/watch?v=LXQfEFEfFcM&t=62s

html：

数据库：

代码：

<?php
$error = NULL;
if (isset($_POST['submit'])) {
    /* Get Form data */
    $e = $_POST['e'];
    $u = $_POST['u'];
    $p = $_POST['p'];
    $p2 = $_POST['p2'];
    $fn = $_POST['fn'];
    $mn = $_POST['mn'];
    $ln = $_POST['ln'];
    $dob = $_POST['dob'];

    if(strlen($u) < 5) {
        /* Username too short */
        $error = '<p style="color: red;">Username must be at least 5 characters</p>';
    } else if($p2 != $p) {
        /* Passwords dont match */
        $error = '<p style="color: red;">Passwords do not match</p>';
    } else {
        /* Form is valid -> Connect to the database */
        $mysqli = NEW MySQLi('localhost', 'root', '', 'test');

        /* Sanitize form data (prevent any sql injection) */
        $e = $mysqli->real_escape_string($e);
        $u = $mysqli->real_escape_string($u);
        $p = $mysqli->real_escape_string($p);
        $p2 = $mysqli->real_escape_string($p2);
        $fn = $mysqli->real_escape_string($fn);
        $mn = $mysqli->real_escape_string($mn);
        $ln = $mysqli->real_escape_string($ln);
        $dob = $mysqli->real_escape_string($dob);

        /* Generate Verification Key + hash password */
        $vkey = md5(time().$u);
        $hashedp = password_hash($p, PASSWORD_DEFAULT);

        /* Insert into database */
        $insert = $mysqli->query("INSERT INTO accounts(email, username, password2, first_name, middle_name, last_name, DOB, vkey) VALUES('$e', '$u', '$hashedp', '$fn', '$mn', '$ln', $dob, '$vkey')");

        $error = 'Sql statement executed';
        $mysqli->error;

        /* Check if data was inserted */
        if($insert) {
            $error = 'Data Inserted';
            $mysqli->error;

            /* Send email */
            $to = $e;
            $subject = "Email Verification";

            $message = "<a href='http://yieldsync.com/verify.php?vkey=$vKey'>Register Account</a>";

            $headers = "From: The Sender Name <[email protected]>\r\n";
            $headers .= "MIME-Version: 1.0"."\r\n";
            $headers .= "Reply-To: [email protected]\r\n";
            $headers .= "Content-type: text/html\r\n";

            mail($to, $subject, $message, $headers);

            header('location: thankyou.php');
        } else {
            $error = 'Data not inserted';
            $mysqli->error;
        }
    }
}
    ?>

<!------------------------------------------------------------------------------------------------------------------->
<?php include 'global-items/header.php'; ?>

<div id="sign-up" class="loginTerminalContainer"> 
    <p class="loginTitle">Sign Up</p>

    <?php echo $error; ?>

    <Form action="" method="post" style="width: 100%;">

        <input name="fn" class="loginTextBox" type="text" placeholder="First Name">
        <input name="mn" class="loginTextBox" type="text" placeholder="Middle (if none -> blank)">
        <input name="ln" class="loginTextBox" type="text" placeholder="Last Name">

        <input name="dob" class="loginTextBox" type="date" placeholder="Date of Birth">

        <input name="e" class="loginTextBox" type="email" placeholder="E-mail" autocomplete="off">
        <input name="u" class="loginTextBox" type="text" placeholder="Username" autocomplete="off">
        <input name="p" class="loginTextBox" type="password" placeholder="Password">
        <input name="p2" class="loginTextBox" type="password" placeholder="Repeat Password">

        <button name="submit" value="Register" type="submit" class="btn btn-primary loginButton">Register</button>
    </form>
</div>

<?php include 'global-items/footer.php'; ?>

我得到的错误是“数据未插入”mysqli 错误：“第 1 行‘password2’列的数据太长”