Please use <code> tags - this will allows the structure in your data to appear properly on this site.

You need to store the values retrieved into a hash. Assuming the values retrieved in a row are in @row, you can store them as:

 my %cats;

  # .. loop to get a row
    # @row contains the retrieved row
    push $cats{ $row[1] }, $row[0]; # "Hash of arrays structure"
  # End of loop to get a row
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Now you need to output the info retrieved:

  for  my $c (sort keys %cats){
     my $values = $cats{ $c };
     print "$c\t", join (" ", @$values), "\n";
  }
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UPDATE: Adding code needed to split the line after a a specified number of items:

  my $ItemsPerLine=3;

  for  my $c (sort keys %cats){
     my $values = $cats{ $c };
     print "$c\t";
    for my $i(0..$#$values){
       $i % $ItemsPerLine==0 and print "\n\t";
       print  $values->[$i], " ";
    }
    print "\n" unless  $#$values % $ItemsPerLine==0;
  }
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