Displaying based on Results in Mysql Query - php

Question

I have an orders table in mysql and in that for some orders I set particular order status like 'review'.
I want to setup a way if any order placed by a particular customer(first and last name) for whom i have previously set order status as 'review' to display a warning in the list.
$sql = "select * from order where firstname = ".$firstname." AND lastname = ".$lastname." AND order_status = 'review';";
$SQLresult = mysql_query("$sql", $DBcon_MySQL);
while($row = mysql_fetch_array($SQLresult)) {
foreach($row as $row){
$result = "warning!";
echo $result;
}
}
The above code does not display anything. please let me know how to fix this.
[EDIT After Applying Answer]
This is how i am using it.
<td width="200">
<?
$sql = "select * from cust_order where firstname = '$firstname' AND lastname = '$lastname' AND order_status = 'review'";
$SQLResult = mysql_query("$sql", $DBcon_MySQL);
while($row = mysql_fetch_array($SQLResult )) {
//$result;
foreach($row as $row ){
//$result="";
$result = "Warning!";
}
?>
<p><? echo $result;?></p>
<?} ?>
</td>
How should i insert a check that it should display warning only once No matter how many orders from single customer are marked as review, display warning only once?

Answer 1

try this,
$sql = "SELECT
*
FROM
`order`
WHERE
firstname = '$firstname' AND lastname = '$lastname' AND
order_status = 'review' LIMIT 1";
$SQLresult = mysql_query($sql, $DBcon_MySQL);
while($row = mysql_fetch_array($SQLresult)) {
foreach($row as $row){
$result = "warning!";
echo $result;
}
}
Please be informed that mysql functions are deprecated and not recommended. USE MySQLi or PDO instead. have a reference from following queries.
http://php.net/manual/en/book.mysqli.php
http://php.net/manual/en/book.pdo.php