my $res = $dbh->selectall_arrayref('select * from table');

foreach my $row (@$res) {
   print join(',', @$row), "\n";
}

# html-table style
print "<table>\n";
foreach my $row (@$res) {
   print "\t<tr>\n";
   print map { "\t\t<td>$_</td>\n" } @$row;
   print "\t</tr>\n";
}
print "</table>\n";