4- Find the names of all students who have taken any Comp. Sci. course ever (there should be no duplicate names). (USE subquery) 5- Find the number of instructors in each department who teach a course in the Spring 2018 semester. 6- Find the names of all instructors, along with their department names and department building name (USE JOIN) section Course id zec_id semester year building room_number time_slot jd classroom building room number capacity takes ID course id sec id semester year grade time_slot time_slot id day start time end time teaches ID course id rec_id semester year course course id title dept_name credits prereq course id prere id student ID name dept_name 101 cred department dept_name building budget instructor ID name dept_name salary advisor aid