[Database class] HW3 answers

[Paul S. Wang]

Dear dbclass,

HW3 grading is done.

Here is a set of good answers for HW3:

/*First query*/
SELECT DISTINCT name from student natural join takes
WHERE course_id LIKE 'CS%'
/*Second query*/
SELECT DISTINCT student.ID, student.name FROM student
WHERE student.ID NOT IN
(SELECT DISTINCT ID FROM takes WHERE
((year=2009 AND semester != 'Fall') OR year < 2009));

/*Third query*/
SELECT dept_name, MAX(salary) AS "Highest salary"
FROM instructor GROUP BY dept_name;

/*Forth query*/
SELECT MIN(max) AS 'Lowest Max Salary' FROM   
(SELECT MAX(instructor.salary) AS max   
FROM instructor group by instructor.dept_name) AS MaxSalary;

-- 
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 Paul S. Wang (王士弘)                      Email: pwang at cs.kent.edu            
 Dept. of Computer Science, Kent State U.   Tel: (330) 672-9051
 Kent, Ohio, USA 44242-0001                 http://www.cs.kent.edu/~pwang/ 
==============================================================================