CREATE TABLE courses (course_id NUMBER, author_id NUMBER, subject_id NUMBER, course_name CLOB, course_description CLOB)
CREATE TABLE student_tests_taken (registration_id NUMBER, date_test_taken TIME, test_result CLOB)
CREATE TABLE student_course_enrolment (registration_id NUMBER, student_id NUMBER, course_id NUMBER, date_of_enrolment TIME, date_of_completion TIME)
CREATE TABLE subjects (subject_id NUMBER, subject_name CLOB)
CREATE TABLE course_authors_and_tutors (author_id NUMBER, author_tutor_atb CLOB, login_name CLOB, password CLOB, personal_name CLOB, middle_name CLOB, family_name CLOB, gender_mf CLOB, address_line_1 CLOB)
CREATE TABLE students (student_id NUMBER, date_of_registration TIME, date_of_latest_logon TIME, login_name CLOB, password CLOB, personal_name CLOB, middle_name CLOB, family_name CLOB)

For each distinct test result, find the number of students who got the result.
SELECT test_result, COUNT(*) FROM student_tests_taken GROUP BY test_result ORDER BY COUNT(*) DESC
SELECT "test_result", COUNT(*) FROM "student_tests_taken" GROUP BY "test_result" ORDER BY COUNT(*) DESC