Eloquent & Carbon Time Difference - php

Question

I have a basic table which captures time and attendance.
I'm trying to out put the total hours on site, from my eloquent query:
$attendance = DB::table('staff_attendances')
->whereBetween('in_date', array($date1, $date2))->where('staff_id', $ID)->select('first_name', 'last_name', 'in_date', 'out_date', 'in_time', 'out_time')->get();
I get the following back in json.
[{"first_name":"TestFirst","last_name":"TestLast","in_date":"2016-01-30","out_date":"2016-01-30","in_time":"11:40:34","out_time":"12:41:10"},
{"first_name":"TestFirst","last_name":"TestLast","in_date":"2016-01-30","out_date":"2016-01-30","in_time":"13:02:27","out_time":"14:02:32"}]
Which method would be best to out put total hours on site?
I've tried using carbon with the following:
$startTime = Carbon::parse($attendance->in_time);
$finishTime = Carbon::parse($attendance->out_time);
$totalDuration = $finishTime->diffInHours($startTime);
But I get "Trying to get property of non-object"

Answer 1

Carbon is a class which extends DateTime class. It should deal with date and/or time. But it looks like your parse call don't return a Carbon instance. So I advise you to use a full date format ("Y-m-d H:i:s") as in the following example :
<?php
$totalDuration = 0;
foreach($attendance as $aAttendance){
$startTime = Carbon::parse($aAttendance->in_date.' '.$aAttendance->in_time);
$finishTime = Carbon::parse($aAttendance->out_date.' '.$aAttendance->out_time);
$totalDuration += intval($finishTime->diffInHours($startTime));
}
?>
With the foreach instruction you will go through all the attendances and do the sum of all diffInHours returns in the variable $totalDuration.