a. List the course number taken by all students named 'John Smith' in winter 1999 (i.e., Semester = 'W99').
π Cnum ( σ Name = 'John Smith' ^ Semester = 'W99' ( COURSE ⨝ ENROLL ⨝ STUDENT ) )
b. Produce a list of textbooks (include Course#, ISBN, Title) for courses offered by the Computer Science Department (i.e., Dept = 'CS').
π Cnum, ISBN, Title ( σ Dept = 'CS' ( TEXTBOOK ⨝ BOOK_ADOPTION ⨝ COURSE ) )
c. List any department that has its adopted books published by 'BC Publishing'.
π Dept ( σ Publisher = 'BC Publishing' ( COURSE ⨝ BOOK_ADOPTION ⨝ TEXTBOOK ) )
d. Find the names of students who have not been enrolled in any course.
π Name ( σ Ssn = NULL (STUDENT ⟕ ENROLL) )
OR
π Name ( STUDENT ) - π Name ( STUDENT ⨝ ENROLL )
e. Find all the textbooks that were authored by Mike Wilkins.
σ Author = 'Mike Wilkins' ( TEXTBOOK )