What are the ids of courses offered in Fall of 2009 but not in Spring of 2010?
SELECT course_id FROM SECTION WHERE semester  =  'Fall' AND YEAR  =  2009 EXCEPT SELECT course_id FROM SECTION WHERE semester  =  'Spring' AND YEAR  =  2010
2009 sonbaharında sunulan, ancak 2010 ilkbaharında sunulan derslerin kimlikleri nelerdir?