Necesitas más o menos algo como esto:
<?php include 'config.php';
$data = mysql_query("SELECT *, TIMESTAMPDIFF(DAY, insurance_date, NOW()) AS expire_date FROM supplier_stats")
or die(mysql_error());
echo "<table class=\"table\" style=\"width:900px; font-family: 'Lucida Grande', Tahoma, Verdana, Arial, sans-serif;
font-size:11px; color:#96969;\" >";
while($row = mysql_fetch_array( $data )) {
$days = $row['expire_date'] -1;
echo "<tr><td><p>".$row['id'] . "</p></td>";
echo "<td><p>".$row['company_name'] . "</p></td>";
if ($days > 0) {
echo "<td><p>Insurance expires in <font color=\"red\">{$row['expire_date']} day(s)!</font></p></td>";
} else {
$when = $days*-1;
echo "<td><p>Insurance expires";
if ($when > 1){
echo " in {$when} days</p></td>";
}
if ($when >= 8){
echo " <div class=\"green_light\"></div>";
}
if ($when <= 7){
echo " <div class=\"red_light\"></div>";
} elseif ($when ===1) {
echo " tomorrow</p></td>";
} elseif ($when == 0) {
echo " today</p></td>";
}
}
echo "<tr>";
}
echo "</table>"; //Close the table in HTML
?>