Insert multiple rows to database from HTML form containing repeated fields using MySQLi

I'm trying to make a form that uses arrays so once it is submitted and processed multiple rows get inserted into my database. My main program is more complex than below but I could not get it working so I decides to create a small simple program to understand the basic syntax better then apply the techniques to the main program. I have got it to work using the depreciated MySQL but converting it to MySQLi is causing problems that I wonder if I can get help with.

My form is set up like this

<html>
<title>multi row insert test form</title>
<body>
<table>
    <form action="process2.php" method="post">
        <tr>
            <th>forename</th>
            <th>surname</th>
            <th>level</th>
        </tr>
        <tr>
            <td><input type="text" name="fname[]"></td>
            <td><input type="text" name="sname[]"></td>
            <td> 
                <select name="level[]">
                    <option value="1">1</option>
                    <option value="2">2</option>
                    <option value="3">3</option>
                    <option value="4">4</option>
                </select>
            </td>
        </tr>
        <tr>
            <td><input type="text" name="fname[]"></td>
            <td><input type="text" name="sname[]"></td>
            <td> 
                <select name="level[]">
                    <option value="1">1</option>
                    <option value="2">2</option>
                    <option value="3">3</option>
                    <option value="4">4</option>
                </select> 
            </td>
        </tr>
        <tr>
            <td><input type="submit" name="submit" value="Submit"></td>
        </tr>
    </form>
</table>
</body>
</html>

and the php page that updates the database using MySQLi is as below

include 'dbconnect2.php';
$fname = $_POST['fname'];
$sname = $_POST['sname'];
$level = $_POST['level'];

if ($stmt = $mysqli->prepare("INSERT INTO people (fname, sname, level) values (?, ?, ?)")) {

    $stmt->bind_param('ssi', $fname, $sname, $level);

    for ($i=0; $i<2; $i++)
    {
        $fname[$i] = $fname;
        $sname[$i] = $sname;
        $level[$i] = $level;

        $stmt->execute();
        echo "Done";
    }

    $stmt->close();
}

Solution

Or, with less rewriting your existing code:

$fnames = $_POST['fname'];
$snames = $_POST['sname'];
$levels = $_POST['level'];

$stmt = $mysqli->prepare("INSERT INTO people (fname, sname, level) values (?, ?, ?)")

for ($i=0; $i<count($fnames); $i++) {
    $fname = $fnames[$i];
    $sname = $snames[$i];
    $level = $levels[$i];
    $stmt->bind_param('ssi', $fname, $sname, $level);

    $stmt->execute();
}
echo "Done";

$stmt->close();