Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Highschooler (id VARCHAR, student_id VARCHAR)
TABLE: CREATE TABLE Friend (id VARCHAR, student_id VARCHAR)

### Question ###
Show ids of all students who do not have any friends.

### Accurate SQL ###

SELECT id FROM Highschooler EXCEPT SELECT student_id FROM Friend