-- Database schema
| Person : name [ TEXT ] primary_key , age [ INT ] , city [ TEXT ] , gender [ TEXT ] , job [ TEXT ] | PersonFriend : name [ TEXT ] PersonFriend.name = Person.name , friend [ TEXT ] PersonFriend.friend = Person.name , year [ INT ] |
-- -- Which person whose friends have the oldest average age?

SELECT T2.name ,  avg(T1.age) FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name  =  T2.friend GROUP BY T2.name ORDER BY avg(T1.age) DESC LIMIT 1;