POST filter_var清理无法正常工作

Question

我有一个用于编辑mysql数据库中多行的代码。 问题在于，当我尝试使用filter_var来清理$_POST时 与filter_var($_POST['toode'], FILTER_SANITIZE_STRING)类似，则值变为空白，数据库中的值将被删除。使用$_POST而不使用filter_var进行清理时，它可以正常工作。  哪个可能是问题？

<?php
    $host="xxx"; 
    $username="xxx"; 
    $password="xxx"; 
    $db_name="xxx"; 
    $tbl_name="xxx"; 

    mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
    mysql_select_db("$db_name")or die("cannot select DB");

    $sql = "SELECT * FROM $tbl_name";
    $result = mysql_query($sql);

    $count = mysql_num_rows($result);
?>

<table width="500" border="0" cellspacing="1" cellpadding="0">
    <form name="form1" method="post" action="">
    <tr> 
        <td>
            <table width="500" border="0" cellspacing="1" cellpadding="0">
            <tr>
                <td align="center"><strong>Id</strong></td>
                <td align="center"><strong>Toode</strong></td>
                <td align="center"><strong>Kogus</strong></td>

            </tr>

            <?php
                while ($rows = mysql_fetch_array($result))
                {
            ?>

            <tr>
                <td align="center">
                    <?php $id[] = $rows['id']; ?>
                    <?php echo $rows['id']; ?>
                </td>

                <td align = "center">
                    <input name="toode[]" type="text" id="toode" value="<?php echo $rows['toode']; ?>">
                </td>

                <td align = "center">
                    <input name="kogus[]" type="text" id="kogus" value="<?php echo $rows['kogus']; ?>">
                </td>

            </tr>

            <?php
                }
            ?>

            <tr>
                <td colspan="4" align="center"><input type="submit" name="submit" value="Submit">
                </td>
            </tr>
            </table>
        </td>
    </tr>
    </form>
</table>

<?php
    if (isset($_POST['submit']))
    {
        $toode = $_POST['toode'];
        $kogus = $_POST['kogus'] ;

        for($i = 0; $i < $count; $i++)
        {
            $sql1 = "UPDATE $tbl_name SET toode='$toode[$i]', kogus='$kogus[$i]' WHERE id='$id[$i]'";
            $result1 = mysql_query($sql1);
        }
    }

    if (isset($result1))
    {
        header("location:uus.php");
    }

?>