-- 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 ] |
-- -- How old is the doctor named Zach?

SELECT age FROM Person WHERE job  =  'doctor' AND name  =  'Zach';