使用Perl和MySql,如何检查空结果？

use DBI;

my $dbh = DBI->connect("DBI:mysql:database=<database_name>;host=<host_name>;port=<port_number>", "<username>", "<password>")
    or die "Could not connect to database: $DBI::errstr";

my $query = "SELECT * FROM <table_name>";
my $sth = $dbh->prepare($query);
$sth->execute();

if ($sth->rows == 0) {
    print "结果集为空\n";
} else {
    while (my $row = $sth->fetchrow_hashref) {
        # 处理结果集中的每一行数据
    }
}

$sth->finish();
$dbh->disconnect();