text: 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 prereq (course_id VARCHAR); CREATE TABLE course (course_id VARCHAR)
  ### Question:
  Find the id of the courses that do not have any prerequisite?
  ### Answer:
  SELECT course_id FROM course EXCEPT SELECT course_id FROM prereq