drop view sales_v;
create view sales_v as
	select
			st.name as �X��,
			it.name as ���i,
			sa.num as �̔���,  
			it.price * sa.num as ������z
		from store st
		cross join item it
		left join sales sa on (st.code, it.code) = (sa.s_code, sa.i_code)
		order by st.code, it.code
;