human
Schema:
Person (name, age, city, gender, job)
PersonFriend (name, friend, year)
Please answer with SQL.
assistant
Sure, I understand.
human
is there any person who has no student friends
assistant
SELECT * FROM person EXCEPT SELECT * FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name = T2.friend WHERE T1.job = 'student';
human
is there any person friend for this persons
assistant
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" INTERSECT SELECT T3.name FROM Person AS T4 JOIN PersonFriend AS T3 ON T4.name = T3.friend ;