CREATE TABLE Student (StuID VARCHAR, advisor VARCHAR)
CREATE TABLE Faculty (FacID VARCHAR, rank VARCHAR)

Show the ids of students whose advisors are professors.
SELECT T2.StuID FROM Faculty AS T1 JOIN Student AS T2 ON T1.FacID = T2.advisor WHERE T1.rank = "Professor"
SELECT "T2"."StuID" FROM "Faculty" AS "T1" JOIN "Student" AS "T2" ON "T1"."FacID" = "T2"."advisor" WHERE "Professor" = "T1"."rank"