Question

I am having problem archiving real time loop. While it going to next iteration, it should check the status first for an update (status= 0) before going to next iteration.

status field might be updated somewhere else…

For example:

<?php
$SQL = "SELECT * FROM data WHERE status = 0";
$query = $db->prepare($SQL);
$query->execute();

while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
    print_r($row);
    print("\n\n");
    sleep(5);
}
?>

While php script is running/looping, in mysql console, I quickly did:

UPDATE data SET status = 1

It is still showing all the records even I have updated the status. How can that problem be fixed?

Answer 1

The result set is only computed once. If you want to see intermediate updates, you need to issue another SELECT statement.