select distinct substring(name,1,1) from stamps ,printsize_master where year(stamps.issue_date)=1966 and month(issue_date)=4 and printsize_master.printsize_code=stamps.printsize_code and printsize_master.printsize='2.99 x 2.1' and stamps.serial_no='0531' order by substring(name,1,1)
IndianPost
Issue Date >> year >> 1966 >> month >> April >> Print Size >> 2.99 x 2.1 >> Serial Number >> 0531 >> Alpha >> K >>