--q12.sql--

 select i_item_id,
  i_item_desc, i_category, i_class, i_current_price,
  sum(ws_ext_sales_price) as itemrevenue,
  sum(ws_ext_sales_price)*100/sum(sum(ws_ext_sales_price)) over
          (partition by i_class) as revenueratio
 from
	web_sales, item, date_dim
 where
	ws_item_sk = i_item_sk
  	and i_category in ('Sports', 'Books', 'Home')
  	and ws_sold_date_sk = d_date_sk
	and d_date between cast('1999-02-22' as date)
				and (cast('1999-02-22' as date) + interval '30' day)
 group by
	i_item_id, i_item_desc, i_category, i_class, i_current_price
 order by
	i_category, i_class, i_item_id, i_item_desc, revenueratio
 LIMIT 100