Hi Swaroop, so you probably want to break it down. Get your data set first by joining the tables involved. Then group the dataset by year, country and material cats and aggregate. You could model this. Then use partition by and window function to get the top 5 for each year country and category from this view - see here for details - http://help.sap.com/saphelp_hanaplatform/helpdata/en/20/a353327519101495dfd0a87060a0d3/content.htm
Hope that helps.
Peter