What are the names of all the persons who are friends with Alice?
select t1.name from person as t1 join personfriend as t2 on t1.name = t2.name where t2.friend = 'Alice'
Okay, could you show me Zach's job?
select job from person where name = "Zach"
How old is Zach?
select age from person where name = "Zach"
How many years has Zach been friends with Alice?
select year from personfriend where friend = "Alice" and name = "Zach"