my @intervals = (
    ['2013-08-01 00:00:00.000', '2013-08-02 00:00:00.000'],
    ['2013-08-02 00:00:00.000', '2013-08-03 00:00:00.000'],
);
...
foreach my $interval (@intervals) {
    $sth->execute(@$interval);
...
}