Table schema:
CREATE TABLE Addresses (address_id VARCHAR, state_province_county VARCHAR); CREATE TABLE Students (last_name VARCHAR, current_address_id VARCHAR); CREATE TABLE Students (last_name VARCHAR, student_id VARCHAR); CREATE TABLE Student_Enrolment (student_id VARCHAR)

Question: Find the last name of the students who currently live in the state of North Carolina but have not registered in any degree program.
SQL: SELECT T1.last_name FROM Students AS T1 JOIN Addresses AS T2 ON T1.current_address_id = T2.address_id WHERE T2.state_province_county = 'NorthCarolina' EXCEPT SELECT DISTINCT T3.last_name FROM Students AS T3 JOIN Student_Enrolment AS T4 ON T3.student_id = T4.student_id