CREATE TABLE person (name CLOB, age NUMBER, city CLOB, gender CLOB, job CLOB)
CREATE TABLE personfriend (name CLOB, friend CLOB, year NUMBER)

What are the names of the people who have no friends who are students?
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'
SELECT "name" FROM "person" EXCEPT SELECT "T2"."name" FROM "person" "T1" JOIN "personfriend" "T2" ON "T1"."name" = "T2"."friend" WHERE "T1"."job" = 'student'