my %items;
my @items;
while ($row = $sth->fetch_hashref()) {
   our $item; local *item = \( $items{ $row->{item_key} } );
   if (!$item) {
      $item = {
         item_key         => $row->{item_key},
         item_description => $row->{item_description},
         item_summary     => $row->{item_summary},
         actions          => [],
      };
      push @items, $item;
   }

   push @{ $item->{action} }, {
      key     => $row->{action_key},
      summary => $row->{action_summary},
   };
}