Simple code for exceeding time [duplicate] - mysql

Question

This question already has an answer here:
SQL Time exceeds
(1 answer)
Closed 9 years ago.
I've written a piece of code to calculate the waiting time for a patient as follows;
$query = "SELECT PatientID, Forename, Surname, Gender, Illness, Priority, Arrival_time, TIME_FORMAT(ABS(TIMEDIFF(CURTIME(), Arrival_time)),'%H hours') as Waiting_Time FROM Patient";
Which displays the following data:
PatientID Forename Surname Gender Illness Priority Waiting Time
625 Max Courts M non-urgent moderate 4 hours
As the example shows; the waiting time is 4 hours;
I need a piece of code to detect and alert when a time is MORE THAN 4 hours; to echo an alert.
Example code I've tried;
if $waitingtime == >4 hours
then echo "patient must be seen!"
EDIT FULL CODE
<?php
$conn = mysqli_connect("localhost","root","") or die ("No connection");
mysqli_select_db($conn, "a&e") or die('Could not select database.');
$query = "SELECT PatientID, Forename, Surname, Gender, Illness, Priority, Arrival_time, TIME_FORMAT(ABS(TIMEDIFF(CURTIME(), Arrival_time)),'%H hours') as Waiting_Time FROM Patient";
$result = mysqli_query($conn, $query) or die("Invalid query");
echo "<table border='1'>
<tr>
<th>PatientID</th>
<th>Forename</th>
<th>Surname</th>
<th>Gender</th>
<th>Illness</th>
<th>Priority</th>
<th>Waiting Time</th>
</tr>";
while ($row = $result->fetch_object()){
echo "<tr>
<td>" . $row->PatientID . "</td>
<td>" . $row->Forename . "</td>
<td>" . $row->Surname . "</td>
<td>" . $row->Gender . "</td>
<td>" . $row->Illness . "</td>
<td>" . $row->Priority . "</td>
<td>" . $row->Waiting_Time . "</td>
</tr>";
}
echo "</table>";
mysqli_close($conn);
?>

Answer 1

I'm using mysql_* for demonstation purposes. You should be using mysqli_* or PDO.
$query = "SELECT PatientID, Forename, Surname, Gender, Illness, Priority, Arrival_time, TIME_FORMAT(ABS(TIMEDIFF(CURTIME(), Arrival_time)),'%H') as Waiting_Time FROM Patient";
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);
if ($row['Waiting_Time '] > 4)
{
echo "patient must be seen!"
}