Consider the following relations:

Student(ssn, name, address, major)

Course(code, title)

Registered(ssn,code)

Answer any FIVE. Each question caries 0.2 marks.

1. List the codes of courses in which at least one student is registered (registered courses)

2. List the titles of registered courses (of those in 1.)

3. List the codes of courses for which no student is registered

4. The titles of courses for which no student is registered.

5. Names of students and the titles of courses they registered to.

6. SSNs of students who are registered for Database Systems or Analysis of Algorithms.