How many courses are taught?
select count ( * ) from courses
How many different course authors are there?
select count ( distinct author_id ) from course_authors_and_tutors
personal name
select t1.personal_name from course_authors_and_tutors as t1 join courses as t2 on t1.author_id = t2.author_id group by t2.author_id order by count ( * ) desc limit 1
what is the family name?
select t1.family_name from course_authors_and_tutors as t1 join courses as t2 on t1.author_id = t2.author_id group by t2.author_id order by count ( * ) desc limit 1
What is the author id?
select t2.author_id from course_authors_and_tutors as t1 join courses as t2 on t1.author_id = t2.author_id group by t2.author_id order by count ( * ) desc limit 1