php: datetime() difference between 2 datetime with 2 variables

Question

I have in my database 4 columns which are:

Date_in | Time_in | Date_out | Time_out

Date_in and Time_in belong together (e.g., 2013-02-18 13

Answer 1

You don't need quotes if you want to evaluate the variables content. In this case, you only need them to create a separation between date and time:

$start_time = new DateTime($list['date_in']." ".$list['time_in']);
$since_start = $start_time->diff(new DateTime($list['date_out']." ".$list['time_out']));

I am using the dot . in order to concatenate variables with an string, in this case the string is a white space.

You can read more about concatenation in the documentation.