CREATE TABLE courses (course_id TEXT, course_name TEXT, course_description TEXT, other_details TEXT)
CREATE TABLE student_course_attendance (student_id DECIMAL, course_id DECIMAL, date_of_attendance TIME)
CREATE TABLE addresses (address_id DECIMAL, line_1 TEXT, line_2 TEXT, city TEXT, zip_postcode TEXT, state_province_county TEXT, country TEXT)
CREATE TABLE people_addresses (person_address_id DECIMAL, person_id DECIMAL, address_id DECIMAL, date_from TIME, date_to TIME)
CREATE TABLE candidate_assessments (candidate_id DECIMAL, qualification TEXT, assessment_date TIME, asessment_outcome_code TEXT)
CREATE TABLE candidates (candidate_id DECIMAL, candidate_details TEXT)
CREATE TABLE students (student_id DECIMAL, student_details TEXT)
CREATE TABLE student_course_registrations (student_id DECIMAL, course_id DECIMAL, registration_date TIME)
CREATE TABLE people (person_id DECIMAL, first_name TEXT, middle_name TEXT, last_name TEXT, cell_mobile_number TEXT, email_address TEXT, login_name TEXT, password TEXT)

How many registed students do each course have? List course name and the number of their registered students?
SELECT T3.course_name, COUNT(*) FROM students AS T1 JOIN student_course_registrations AS T2 ON T1.student_id = T2.student_id JOIN courses AS T3 ON T2.course_id = T3.course_id GROUP BY T2.course_id
SELECT "T3"."course_name", COUNT(*) FROM "students" AS "T1" JOIN "student_course_registrations" AS "T2" ON "T1"."student_id" = "T2"."student_id" JOIN "courses" AS "T3" ON "T2"."course_id" = "T3"."course_id" GROUP BY "T2"."course_id"