CREATE TABLE Person (
  name varchar(20) PRIMARY KEY,
  age INTEGER,
  city TEXT,
  gender TEXT,
  job TEXT
)

CREATE TABLE PersonFriend (
  name varchar(20),
  friend varchar(20),
  year INTEGER,
  FOREIGN KEY (name) REFERENCES Person(name),
  FOREIGN KEY (friend) REFERENCES Person(name)
)
SELECT name FROM person EXCEPT SELECT T2.name FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name  =  T2.friend WHERE T1.job  =  'student'
What are the names of the people who have no friends who are students?