Set proper conditional statement in WHILE LOOP - php

Question

After submitting a mysqli_query to select open/unfulfilled orders from a cart database the results is output to the screen with a standard WHILE LOOP.
while($row = mysqli_fetch_array($oresult)) { include('orders-open.php');}
orders-open.php is simply the internal part of a TABLE:
<tr style="color:#FFF;">
<td><?php echo $row['Buyer']; ?></td>
<td><?php echo $row['Cart_Date']; ?></td>
<td><?php echo $row['Item_Number']; ?></td>
<td><?php echo $row['Item_Title']; ?></td>
<td><?php echo $row['Item_FPrice']; ?></td>
<td><?php echo $row['Item_Qty']; ?></td>
</tr>
So here is my question, I want to apply a simple HTML "<HR>" tag between the records at the point where the value in $row['Buyer'] changes, so by example:
John Doe 9/11/13 123456 Item 1 $5.99 5
John Doe 9/11/13 123654 Item 2 $8.99 3
John Doe 9/9/13 321456 Item 3 $4.99 2
(HR - Horizontal Rule Tag here)
Mike Doe 9/7/13 123555 Item 1 $9.99 2
Mike Doe 9/7/13 123777 Item 2 $2.99 6
What would be the best way to write the conditional statement inside the WHILE LOOP to compare the $row[Buyer'] result to the previous $row['Buyer'] result?

Answer 1

$first_run = TRUE;
$previous_buyer = NULL;
while($row = mysqli_fetch_array($oresult)) {
if($first_run) {
$first_run = FALSE;
$previous_buyer = $row['Buyer'];
}
include('orders-open.php');
}
And then in your include file:
<?php if($previous_buyer != $row['Buyer']) {
echo '<HR width="100%">';
$previous_buyer = $row['Buyer'];
} ?>
<tr style="color:#FFF;">
<td><?php echo $row['Buyer']; ?></td>
<td><?php echo $row['Cart_Date']; ?></td>
<td><?php echo $row['Item_Number']; ?></td>
<td><?php echo $row['Item_Title']; ?></td>
<td><?php echo $row['Item_FPrice']; ?></td>
<td><?php echo $row['Item_Qty']; ?></td>
</tr>

Answer 2

$prev_buyer = '';
while($row = mysqli_fetch_array($oresult))
{
if($prev_buyer !== $row['Buyer'])
{
//Do Something
}
include('orders-open.php');
$prev_buyer = $row['Buyer']
}

Answer 3

Just as Elon said above - change this:
while($row = mysqli_fetch_array($oresult)) { include('orders-open.php');}
to
$old_buyer = null;
while($row = mysqli_fetch_array($oresult)) {
if ($row['Buyer'] != $old_buyer) {
echo '<hr>';
}
$old_buyer = $row['Buyer'];
include('orders-open.php');
}

Answer 4

You could do it like this:
$buyer = null ; //Cache buyer in a variable, because $row is reset in the loop.
while($row = mysqli_fetch_array($oresult)) {
include('orders-open.php');
if ($buyer !== $row["Buyer"]){
echo ($buyer !== null) ? "<hr/>" : "" ;
$buyer = $row["Buyer"] ;
}
}