Find the average price of wines.
select avg(price) from wine
how about for the wines with appellations from Sonoma county?
select avg(t2.price) from appellations as t1 join wine as t2 on t1.appelation = t2.appelation where t1.county = 'Sonoma'
what is the average for wines that are not produced from there?
select avg(price) from wine where appelation not in (select t1.appelation from appellations as t1 join wine as t2 on t1.appelation = t2.appelation where t1.county = 'Sonoma')