use warnings;
use diagnostics;

use Spreadsheet::XLSX;
use Text::CSV;

my $excel = Spreadsheet::XLSX->new ("Sample.xlsx");
my $csv   = Text::CSV->new ({ binary => 1, auto_diag => 1, eol => "\n" });

foreach my $sheet (@{$excel->{Worksheet}}) {
    printf ("Sheet: %s\n", $sheet->{Name});

    #my @worksheet = qw(sheet1 sheet2);

    my $Minrow = 1;
    my $maxrow = $sheet->{MaxRow} || $Minrow;
    my @wanted_cols = (8, 9, 10, 20);

    open my $fh, ">", "new.csv" or die "new.csv: $!";

    foreach my $row ($Minrow .. $maxrow) {
        $csv->print ($fh,
            [ map { $sheet->{Cells}[$row][$_]{Val} } @wanted_cols ]};
        }
    close my $fh or die "new.csv: $!";
    }