Table schema:
CREATE TABLE PersonFriend (friend VARCHAR, name VARCHAR, year VARCHAR); CREATE TABLE PersonFriend (YEAR INTEGER, name VARCHAR); CREATE TABLE Person (age VARCHAR, name VARCHAR)

Question: What is the age of the friend of Zach with longest year relationship?
SQL: SELECT T1.age FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name = T2.friend WHERE T2.name = 'Zach' AND T2.year = (SELECT MAX(YEAR) FROM PersonFriend WHERE name = 'Zach')