第一行数据没有显示在表php中

when i view the records from the database. the first record doesn't show on the page. when I add the second record and on, they are displayed on the page except the first record that I entered. i don't know why is that. i attached code i tried so so.

$last_insert_id = $_GET['last_id']; this id is coming from purchase page. get the id and put select statement and view relevent record match the id.

$sql = "select i.pur_id,i.prod_id,i.buyprice,i.qty,i.total,p.date,p.total,p.pay,p.due from purchase_item i, purs p where i.pur_id = p.id and  i.pur_id = '278' ";

there are 7 row data include in 278 id. but display only 6 rows

<?php
$x = 1;
$last_insert_id = $_GET['last_id'];
$sql = "select i.pur_id,i.prod_id,i.buyprice,i.qty,i.total,p.date,p.total,p.pay,p.due from purchase_item i, purs p where i.pur_id = p.id and  p.id = $last_insert_id ";
$orderResult = $conn->query($sql);
$orderData = $orderResult->fetch_array();

while ($row = $orderResult->fetch_array()) {
    ?>
    <tr>
        <td class="text-center">
            <?php echo $x; ?>
        </td>
        <td class="text-center">
            <?php echo $row[6]; ?>
        </td>
        <td class="text-center">
            <?php echo $row[3]; ?>
        </td>
        <td class="text-center"><?php echo $row[2]; ?></td>
        <td class="text-right"><?php echo $row[4]; ?></td>
    </tr>

    <?php
    $x++;
}
?>