my $dbh = DBI->connect("dbi:mysql:db", "user", "pass",
              { AutoCommit => 1, RaiseError => 1})
                or die &error_out;
my $qry = $dbh->prepare("SELECT location FROM people")
                or die &error_out;  
$qry->execute or die &error_out;


##</code><code>##

$qry->give_me_the_size_of_the_resultset; ?  :)