CREATE TABLE follows (f1 VARCHAR(255), f2 VARCHAR(255)); CREATE TABLE user_profiles (uid VARCHAR(255), name VARCHAR(255))
Find the id of users who are followed by Mary and Susan.
    
SQL: SELECT T2.f1 FROM user_profiles AS T1 JOIN follows AS T2 ON T1.uid = T2.f2 WHERE T1.name = "Mary" INTERSECT SELECT T2.f1 FROM user_profiles AS T1 JOIN follows AS T2 ON T1.uid = T2.f2 WHERE T1.name = "Susan"