SQL display the highest number Function using MAX() Function

The purpose of this is to display highest number value from specific field of a table's Msql Database.

code to paste:

//protected area orig3 file
$query = "SELECT MAX(ttravelid) FROM travelid";
$resultx = mysql_query($query) or die(mysql_error());
while($row = mysql_fetch_array($resultx))
{
//echo "The most highest reservation id is ".$row['MAX(reservationid)'];
$ttravelid1 = $row['MAX(ttravelid)'];
//or your can display this side echo $ttraveliddd;
}

echo "the highest number is:<br>";
echo $ttravelid1;