I would look into using DBIx::Class to count a particular column.

use strict;
use warnings;
use DBIx::Class;

my $rs = $schema->resultset('YOURTABLENAMEHERE')->search(
{},
  {
    columns => [ qw/name/ ],
    distinct => 1
  }
);

my $count = $rs->count;
[download]

That was basically straight from here: https://metacpan.org/pod/distribution/DBIx-Class/lib/DBIx/Class/Manual/Cookbook.pod