my $sth = $dbh->prepare("select * from finalLevel3 where id=?");
foreach $item (@{$clusters}) {
    $ID = $units[$i][0];
    unless (eval {
      @row = $dbh->selectrow_array($sth, undef, $ID);
      1
    }) {
      die "Error on ID [$ID]: $@";
    }

    # convert the mysql result back to a string again
    $promoter_line = join "\t", @row;
    $promoter_line .= "\n";
   
    $parser_hash{$item} .= $promoter_line;
    $i++;
}