Show the locations that have both performances with more than 2000 attendees and performances with less than 1000 attendees.
SELECT LOCATION FROM performance WHERE Attendance  >  2000 INTERSECT SELECT LOCATION FROM performance WHERE Attendance  <  1000
locations with performances more than 2000 attendees refers to WHERE Attendance > 2000; locations with performances less than 1000 attendees refers to WHERE Attendance < 1000; requiring locations to have both is achieved by using INTERSECT;