Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE teaches ( id VARCHAR, semester VARCHAR, YEAR VARCHAR )

### Question ###
Find the id of instructors who taught a class in Fall 2009 but not in Spring 2010.

### Accurate SQL ###

SELECT id FROM teaches WHERE semester = 'Fall' AND YEAR = 2009 EXCEPT SELECT id FROM teaches WHERE semester = 'Spring' AND YEAR = 2010