CREATE TABLE Student_Course_Enrolment (registration_id NUMBER, student_id NUMBER, course_id NUMBER, date_of_enrolment DATETIME, date_of_completion DATETIME)
CREATE TABLE Subjects (subject_id NUMBER, subject_name VARCHAR2)
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 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 Student_Tests_Taken (registration_id NUMBER, date_test_taken DATETIME, test_result VARCHAR2)

Visualize a bar chart about the distribution of login_name and author_id .
SELECT login_name, author_id FROM Course_Authors_and_Tutors ORDER BY personal_name
SELECT "login_name", "author_id" FROM "Course_Authors_and_Tutors" ORDER BY "personal_name"