my $sth = $dbh->prepare('
   SELECT characters.first, characters.last
   FROM characters
   INNER JOIN people_characters
   ON characters.id = people_characters.characters 
   INNER JOIN people
   ON people_characters.people = people.id 
   WHERE people.first = ?
   AND people.last = ?
   ORDER by characters.last, characters.first
');
$sth->execute(qw(John Smith));
while (my $row = $sth->fetchrow_hashref) {
   print "$row->{first} $row->{last}\n";
}