select distinct substring(name,1,1) from stamps ,paper_master,np_master where year(stamps.issue_date)=1966 and month(issue_date)=4 and paper_master.paper_code=stamps.paper_code and paper_master.paper='Unwatermarked paper' and np_master.np_code=stamps.np_code and np_master.np='P' order by substring(name,1,1)
IndianPost
Issue Date >> year >> 1966 >> month >> April >> Paper >> Unwatermarked paper >> Currency >> P >> Alpha >> D >>