SELECT
    group, somedata
  FROM
    table
  ORDER BY
    group, somedata

##</code><code>##

  my $lastgroup = undef;
  while ( my $row = $sth->fetchrow_arrayref() ) {
    if ( $lastgroup ne $row->[0] ) {
      print( $row->[0] . "\n" );
      $lastgroup = $row->[0];
    }
    print( "  " . $row->[1] . "\n" );
  }

##</code><code>##

  my $lastgroup = undef;
  while ( my $row = $sth->fetchrow_arrayref() ) {
    if ( ( !defined( $lastgroup ) ) || 
         ( $lastgroup ne $row->[0] ) )
    {
      print( $row->[0] . "\n" );
      $lastgroup = $row->[0];
    }
    print( "  " . $row->[1] . "\n" );
  }