CREATE TABLE candidates (candidate_id DECIMAL, candidate_details TEXT)
CREATE TABLE candidate_assessments (candidate_id DECIMAL, qualification TEXT, assessment_date TIME, asessment_outcome_code TEXT)
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)
CREATE TABLE student_course_registrations (student_id DECIMAL, course_id DECIMAL, registration_date TIME)
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 courses (course_id TEXT, course_name TEXT, course_description TEXT, other_details TEXT)
CREATE TABLE people_addresses (person_address_id DECIMAL, person_id DECIMAL, address_id DECIMAL, date_from TIME, date_to TIME)
CREATE TABLE students (student_id DECIMAL, student_details TEXT)

What are the details of the student who registered for the most number of courses?
SELECT T1.student_details FROM students AS T1 JOIN student_course_registrations AS T2 ON T1.student_id = T2.student_id GROUP BY T1.student_id ORDER BY COUNT(*) DESC LIMIT 1
SELECT "T1"."student_details" FROM "students" AS "T1" JOIN "student_course_registrations" AS "T2" ON "T1"."student_id" = "T2"."student_id" GROUP BY "T1"."student_id" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1