Converting ordering via date and time php - php

Question

I have 3 tables of data stored in a database each containing a date and a time field. I'm pulling all the relevant data from each table and concatenating them to an array. I now need to sort the array on date first and then time. I'm currently sorting by date at that works fine but the time sometimes can be right and is sometimes wrong
What I'm currently using to gather the data:
$results = [];
$sql_assign = mysql_query("SELECT * FROM `tk_assign` WHERE ticket_id = $tk_id");
$sql_update = mysql_query("SELECT * FROM `tk_update` WHERE ticket_id = $tk_id");
$sql_status = mysql_query("SELECT * FROM `tk_status_change` WHERE ticket_id = $tk_id");
while($row = mysql_fetch_assoc($sql_assign)){
$results[] = $row;
}
while($row = mysql_fetch_assoc($sql_update)){
$results[] = $row;
}
while($row = mysql_fetch_assoc($sql_status)){
$results[] = $row;
}
What I'm using to sort it
$orderByDate = $my2 = array();
foreach($results as $key=>$row)
{
$my2 = explode('/',$row['date']);
$my3 = explode('/',$row['time']);
$my_date2 = $my2[1].'/'.$my2[0].'/'.$my2[2];
$orderByDate[$key] = strtotime($my_date2);
}
$sorted = array_multisort($orderByDate, SORT_ASC, $results);
I've thought about turning it into timecodes but that hasn't worked either. Any help would be greatly appreciated
Example time and date:
Date: 22/09/2015 Time: 15:32:12
Date: 22/09/2015 Time: 14:50:28
Date: 25/09/2015 Time: 12:21:58

Answer 1

I think this line is wrong:
$my3 = explode('/',$row['time']);
It probably should be:
$my3 = explode(':',$row['time']);
In any case, you're not even using the $my3 variable in your sorting algorithm.
Here's another solution. Just after merging the arrays, add the following code:
for ($i =0; $i < count($results); $i++){
$results[$i]['datetime'] = $results[$i]['date'].' '.$results[$i]['time'];
}
function compareDateTime($a, $b) {
$mya = new DateTime();
$mya->createFromFormat('d/m/Y H:i:s', $a['datetime']);
$myb = new DateTime();
$myb->createFromFormat('d/m/Y H:i:s', $b['datetime']);
if ($mya == $myb)
return 0;
if ($mya > $myb)
return 1;
return -1;
}
usort($results, 'compareDateTime');

Answer 2

If you are using PHP > 5.2 then you should use following way.
$orderByDate = $my2 = array();
foreach($results as $key=>$row)
{
$myDateTime = DateTime::createFromFormat('d/m/Y', $date);
$newDateString = $myDateTime->format('Y-m-d');
$orderByDate[$key] = strtotime($newDateString." ".$row['time']);
}
$sorted = array_multisort($orderByDate, SORT_ASC, $results);