how do I sum two time variable in format H-i-m in php? [duplicate]

Question

I want to calculate total working hours of an employee for a month.The time for one session of an employee is stored in the format 'H:i:s' as as string in the database.How do I add these individual sessions to calculate total time.

Answer 1

The function strtotime(datetime_today) will parse to seconds relative to the difference between the current datetime and 01/01/1970

<?php

$datetime_ref_today = '0:00:00';

$ar_times[]='00:00:10';
$ar_times[]='00:01:30';
$ar_times[]='13:50:30';

$total_time = 0;
foreach($ar_times as $val)
{
  $total_time += strtotime($val)-strtotime($datetime_ref_today);
  echo "<br/>cumul. total_time : ".$total_time." sec";;
}

echo "<br/><br/>total_time : ".$total_time." sec";
echo "<br/>Formated total_time (H:i:s): ".gmdate("H:i:s", $total_time);
?>