Here's a subroutine that you can send those two time stamps to for the desired output (returns 0 if no intersecting time):

use Modern::Perl;
use Date::Calc qw/ Date_to_Time Time_to_Date /;

say intersectingTime(
    '2012-08-17 12:00:00',
    '2012-08-17 13:00:00',
    '2012-08-17 09:00:00',
    '2012-08-17 12:30:00'
);

sub intersectingTime {
    my ( $s1, $e1, $s2, $e2 ) = map Date_to_Time( /\d+/g ), @_;
    my $tStart = $s1 > $s2 ? $s1 : $s2;
    my $tEnd   = $e1 < $e2 ? $e1 : $e2;

    $tEnd <= $tStart
      ? 0
      : sprintf '%4d-%02d-%02d %02d:%02d:%02d for %02d minutes',
      Time_to_Date( $tStart ), ( $tEnd - $tStart ) / 60;
}

[download]

Output:

2012-08-17 12:00:00 for 30 minutes

[download]

In reply to Re: timestamp manipulation and evaluation by Kenosis
in thread timestamp manipulation and evaluation by jonathancnewcomb

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