Sort array by date, then by time - PHP
<p>i have a booking system that uses for bookings an array in this form:</p>

<pre><code>array(6) {
[0]=&gt; array(5) {
      ["date"]=&gt; string(10) "08/12/2016"
      ["start"]=&gt; string(5) "15:00"
      ["end"]=&gt; string(5) "16:00"
      ["booked_by"]=&gt; string(5) "mark"
      ["id"]=&gt; string(1) "4"
}
</code></pre>

<p>I used this function to sort it by date and to get all bookings in an array:</p>

<pre><code>    function getBooking($aula) {
    global $client;
    $keys = $client-&gt;keys("Calendar:aula$aula:*");
    $booking = array();

    foreach ($keys as $key =&gt; $value) {
        $result = $client-&gt;hGetAll($value);
        array_push($booking, $result);
    }

    usort($booking, function($a1, $a2) {
        $v1 = strtotime(str_replace("/", "-", $a1['data']));
        $v2 = strtotime(str_replace("/", "-", $a2['data']));
        return $v1 - $v2; // $v2 - $v1 to reverse direction
    });

    return $booking;
}
</code></pre>

<p>I need to sort it also by "start" key to show them in a calendar. I tried adding another usort but it doesn't work. If you need more info please write me back
Thanks in advance for you help</p>