Write the following SQL queries

Here are the SQL tables Student(snum, sname, major, level, age) Class(name, meets_at, room, fid) Enrolled(snum, cname) Faculty(fid, fname, deptid) Grade(snum, cname, score) Prerequisite(name, prereqcname) Find names of Students who have enrolled in some classes, but have not yet received any grades for any of those classes. For each class, print the name of the class and name of the student who topped the class. If 2 students have the same score, select the one who is younger. Find the 2nd topper for class 'Operating System Design'. If there are two students with the same score, select the one whose name is lexicographically smallest. Query to check if 2 students have the same name. Rank each student for the class 'Operating System Design'. For example, one who has scored highest will have rank 1, second highest will have rank 2 and so on. If 2 students have scored the same, they will have the same rank