Page wont load and server crashes during PHP while loop - php

Question

I am trying to run a php script that says basically, whilst two cells in my MySQL database are empty (t_trailerarrival and t_endsort), do something.
My code is as follows:
<?php
// Start Session, include authentication and dBConnection script
session_start();
include 'dbcon.php';
include 'sql_actuals.php';
$current_time = date("G");
while($query9_row['a_trailerarrival'] == NULL && $query10_row['a_endsort'] == NULL) {
echo "Trailer Arrival";
}
The $queryx_row['abc'] are all in the sql_actuals script that is included into this script.
For some reason, every time i run this script - my browser wont load the result (just loads for ever) and then my website at windows azure seems to crash and take a few minutes to restart.
Could someone please advise if there is a massively obvious error with my script? or point me at what the possible issue could be.
Many thanks in advance.
FYI, i have tried adding a line sleep(1); so that it gave the server it runs off a delay before having to run the program again but no luck.

Answer 1

You are never closing the while loop.
while($query9_row['a_trailerarrival'] == NULL && $query10_row['a_endsort'] == NULL) {
echo "Trailer Arrival";
}
Without modifying the while conditions during a while statement, once you start, you'll never stop. Therefore hanging the script and server.

Answer 2

You are not actually doing anything in your while statement except echoing a line.
Therefore
$query9_row['a_trailerarrival'] == NULL
and
$query10_row['a_endsort'] == NULL
are always true and never changing, and it will never exit the while loop. You need to put exit criteria in the while loop, such as:
$i=0;
while(($query9_row['a_trailerarrival'] == NULL
&& $query10_row['a_endsort'] == NULL )
|| $i==10) {
$i++;
echo "Trailer Arrival";
}
Although, logically speaking, you still need to run the query data.
** Edit **
Based upon your feedback, this doesn't sound like a while loop at all, but rather an if statement you need (with multiple elseif s).
if ($query9_row['a_trailerarrival'] == NULL && $query10_row['a_endsort'] == NULL){
echo "Trailer Arrival";
} elseif ($query9_row['a_trailerarrival'] == NULL && $query10_row['a_endsort']){
echo "End Sort";
} elseif ($query9_row['a_trailerarrival'] && $query10_row['a_endsort']){
echo "First Van";
}else {
// fourth condition:
// $query9_row['a_trailerarrival'] != NULL && $query10_row['a_endsort'] == NULL
}
I included a fourth condition when $query9_row isn't null, and $query10_row is null.