if ($row->{start_date} ne $last_date && (split/:/,$row->start_time)[0]
+ > 9) {
[download]

update: Oops. That will output incorrect results if all entries for a day are from before 9:00. Make a hash keyed with unix timestamps of each date, push each entry onto an array for the appropriate day:

use Time::Local;
...
for my $row (@rows) {
    my @l = reverse split /-/, $row->{start_date};
    $l[1]--; # months range is 0..11
    my $key = timelocal(0,0,0,@l);
    my $line = join("\t", $row->{id_number}, $row->{start_time}); # wh
+atever formatting

    if(split/:/,$row->start_time)[0] > 9) {
        push @{$hash{$key-86400}}, $line;
    } else {
        push @{$hash{$key}}, $line;
    }
}
foreach my $key (sort %hash) {
    my @l = (localtime $key)[5,4,3];
    $l[1]++; # month...
    print join('-', @l), "\n";
    print $_,"\n" for @{$hash{$key}};
}
[download]

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}