my $sth = $dbh->prepare("SELECT a.name,b.name as capital, a.continent,a.region, a.lifeexpectancy,a.surfacearea,a.population FROM country a, city b WHERE a.capital=b.id ORDER BY 1");
$dbh->do("SET search_path to world") or die;
$sth->execute();

my $row=1;
while ($a = $sth->fetchrow_hashref()) {
$worksheet->write($row,0, $a->{name}, $bold);
$worksheet->write($row,1, $a->{capital});
$worksheet->write($row,2, $a->{continent});
$worksheet->write($row,3, $a->{region});
$worksheet->write($row,4, $a->{lifeexpectancy});
$worksheet->write($row,5, $a->{surfacearea});
$worksheet->write($row,6, $a->{population});
$row++;
}