my %h;

...; # get info from db

$h{$total} += $revenue;

##</code><code>##

use warnings;
use strict;

use Data::Dumper;

my %h;

while (<DATA>){
    my ($total, $revenue) = split;
    $h{$total} += $revenue;
}

print Dumper \%h;

__DATA__
3 555
4 962
3 1
3 1064
5 19
17 8
45 -1

##</code><code>##

$VAR1 = {
          '5' => 19,
          '3' => 1620,
          '45' => -1,
          '4' => 962,
          '17' => 8
        };