my @columns = ("ID","value","some_other_column");
my %rows;
while (my @row = $sth5->fetchrow_array) {
   my %rowHash = ();
   for (my $i=0; $i < scalar @row; $i++) {
      $rowHash{$columns[$i]} = $row[$i];
   }
   $rows{$row[0]} = \%rowHash;
}