What are the positions of both players that have more than 20 20 points and less than 10 points?
SELECT POSITION FROM player WHERE Points  >  20 INTERSECT SELECT POSITION FROM player WHERE Points  <  10
positions of players with more than 20 points refers to Points > 20; positions of players with less than 10 points refers to Points < 10; using INTERSECT to find common positions meeting both criteria;