Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE Highschooler (id VARCHAR, student_id VARCHAR); CREATE TABLE Friend (id VARCHAR, student_id VARCHAR)
### Question:
Show ids of all students who do not have any friends.
### Answer:
SELECT id FROM Highschooler EXCEPT SELECT student_id FROM Friend