Database: student_transcripts_tracking
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