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 student_course_attendance (student_id VARCHAR); CREATE TABLE student_course_registrations (student_id VARCHAR)
  ### Question:
  What are the id of students who registered courses or attended courses?
  ### Answer:
  SELECT student_id FROM student_course_registrations UNION SELECT student_id FROM student_course_attendance