Help needed in billing project sql server database related

Question

i have build a billing project for a firm i which it make a bill and dispatch challan. i have to make the sql server database which can show the pervious finacial year record with present year record. every new finacial year start the bill and challan no is been reset. Perviously i have to backup the pervious finacial database and delete the recond then only the new finacial year record start with new billing number and challan number, i need a help in such that when we select the privious finacial year record it will show the record with the present finacial year record (like if we select finacial year 2015-2016 it will show the record of the 2015-2016 with the present finacial year 2016-2017 year record). i need the example with demo example so that i can show to the firm with the example please need me urgently needed.