3.11
Lowercase your answer:
# a.
SELECT `name`
FROM student NATURAL JOIN takes NATURAL JOIN course
WHERE dept_name = 'Comp. Sci.'
# b.
SELECT `ID`, `name`
FROM student
EXCEPT
SELECT `ID`, `name`
FROM student NATURAL JOIN takes
WHERE `year` < 2009
# c.
SELECT `dept_name`, MAX(salary)
FROM instructor
GROUP BY dept_name
#d.
SELECT MAX(salary)
FROM
(SELECT `dept_name`, MAX(salary)
FROM instructor
GROUP BY dept_name)
3.12
# a.
INSERT INTO course
VALUES('CS-001', 'Weekly Seminar', 'Comp. Sci.', 0)
# b.
INSERT INTO section(`year`, semester, sec_id)
VALUES('2009', 'Fall', 1)
# c.
INSERT INTO takes
SELECT ID, 'CS-001', 1, 'Fall', '2009', NULL
FROM student
WHERE dept_name = 'Comp. Sci.'
# d.
DELETE FROM takes
WHERE course_id = 'CS-001' AND sec_id = 1 AND semester = 'Fall' AND `year` = 2009
AND ID IN
(SELECT ID
FROM student
WHERE `name` = 'Chavez')
# e.
DELETE FROM takes
WHERE course_id = 'CS-001'
DELETE FROM section
WHERE course_id = 'CS-001'
DELETE FROM course
WHERE course_id = 'CS-001'
#The above order cannot be changed because the course_id foreign code of takes depends on section.
# The course_id foreign code of section depends on course. Changing the order will cause foreign code conflicts.
# f.
DELETE FROM takes
WHERE course_id IN
(SELECT course_id
FROM course
WHERE LOWER(title) LIKE '%database%')
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