PHP: Timestamp sorting - php

Question

I am making an image website and I need help with timestamp sorting. I have about 5 different SQL queries to get information from the database. Each one of these queries get the timestamp.
What I want to do is get it from the database, and sort the images from all of the queries with a foreach loop. This may sound confusing, just comment if you don't understand.
$images = array();
$stmt = $conn->prepare("SELECT images.*, group_images.* ORDER BY `timestamp` DESC");
$stmt->execute();
while ($images_row = $stmt->fetch(PDO::FETCH_ASSOC)) {
$images[] = array(
'image_id' => $images_row['image_id']);
}
return $images;
foreach($images as $image) {
echo $image['image_id'];
echo '<br/>';
}
That is a query I attempted to try which turned out not to work.
Error:
$images = valley_images();
$sorted_data = array();
foreach($images as $key => $value) {
if ($key == 'timestamp') {
$sorted_data[$value][] = $images;
}
}
ksort($sorted_data);

Answer 1

If I understand you correctly, this might help:
$data; //data from database, assuming it has a "timestamp"-key
$sorted_data = array();
foreach ($data as $key => $value) {
if ($key == 'timestamp') {
$sorted_data[$value][] = $data;
}
}
ksort($sorted_data);
With that you get an array that is ordered by the timestamps of your values from the database. If there is only one entry to each timestamp you can spare the [].