What are the names of all reviewers that have given 3 or 4 stars for reviews?
SELECT T2.name FROM Rating AS T1 JOIN Reviewer AS T2 ON T1.rID  =  T2.rID WHERE T1.stars  =  3 INTERSECT SELECT T2.name FROM Rating AS T1 JOIN Reviewer AS T2 ON T1.rID  =  T2.rID WHERE T1.stars  =  4
names of all reviewers refers to SELECT T2.name; given 3 or 4 stars for reviews refers to WHERE T1.stars = 3 INTERSECT WHERE T1.stars = 4; joining tables to link reviewers with their ratings refers to JOIN Reviewer AS T2 ON T1.rID = T2.rID;