how many wines are there?
select count(*) from wine
how many are made of red color grape?
select count(*) from grapes as t1 join wine as t2 on t1.grape = t2.grape where t1.color = "Red"
only show their names.
select distinct t2.name from grapes as t1 join wine as t2 on t1.grape = t2.grape where t1.color = "Red"