CREATE TABLE Course_Authors_and_Tutors (author_id NUMBER, author_tutor_ATB VARCHAR2, login_name VARCHAR2, password VARCHAR2, personal_name VARCHAR2, middle_name VARCHAR2, family_name VARCHAR2, gender_mf VARCHAR2, address_line_1 VARCHAR2)
CREATE TABLE Student_Course_Enrolment (registration_id NUMBER, student_id NUMBER, course_id NUMBER, date_of_enrolment DATETIME, date_of_completion DATETIME)
CREATE TABLE Student_Tests_Taken (registration_id NUMBER, date_test_taken DATETIME, test_result VARCHAR2)
CREATE TABLE Courses (course_id NUMBER, author_id NUMBER, subject_id NUMBER, course_name VARCHAR2, course_description VARCHAR2)
CREATE TABLE Students (student_id NUMBER, date_of_registration DATETIME, date_of_latest_logon DATETIME, login_name VARCHAR2, password VARCHAR2, personal_name VARCHAR2, middle_name VARCHAR2, family_name VARCHAR2)
CREATE TABLE Subjects (subject_id NUMBER, subject_name VARCHAR2)

A bar chart for returning the number of the completion date for all the tests that have 'Fail' result, and order y-axis from low to high order please.
SELECT date_of_completion, COUNT(date_of_completion) FROM Student_Course_Enrolment AS T1 JOIN Student_Tests_Taken AS T2 ON T1.registration_id = T2.registration_id WHERE T2.test_result = "Fail" ORDER BY COUNT(date_of_completion)
SELECT "date_of_completion", COUNT("date_of_completion") FROM "Student_Course_Enrolment" "T1" JOIN "Student_Tests_Taken" "T2" ON "Fail" = "T2"."test_result" AND "T1"."registration_id" = "T2"."registration_id" ORDER BY COUNT("date_of_completion")