Problem 1. Please create the following tables with appropriate primary keys & foreign keys. The list of tables is: • Student table with 2 columns: sid (student ID), sname (student name). • Teacher table with 2 columns: tid (teacher ID), tname (teacher name) • Class table with 6 columns: cid (class ID), cname (class name), year (year of class), semester (semester of class, e.g., fall, spring), credit (number of credits), tid (teacher ID). • Grades table with 3 columns: sid (student ID), cid (class ID), grade (grade, 4 is A, 3 is B, 2 is C, 1 is D, 0 is F). Problem 2. Insert at least three rows of data to each table. Make sure you keep the primary key and foreign key constraints. Problem 3. Please write ONE SQL statement for each of the following tasks using tables created in Problem 1. Task 1: Return the total number of students Task 2: Return the names of classes offered in Spring 2016 (spring is semester, 2016 is year). Task 3: Return the names of classes taught by Dr. Chen in 2016. Task 4: Return the IDs of classes with at least 2 students taking the class. Task 5: Return the names of students who ever took Dr. Chen’s classes. Task 6: Return the average grade of class IS 633 offered in spring 2016. Solution studenttable sid             sname 10              pavan 20              sai 30             praveen teachertable: tid       tname 11       ravi 12       samba 13       murthy classtable cid         cname      year        semster   credit      tid 22          saint           2016       2              a        11 23          mort           2015        1             b         12 grade sid   cid     grade 10   22         a 20   23         b task1: select * from studenttable; task2:select * from classtable where year=2016; task3:select cname from classtable where teachertable.tid =classtable.tid and teachertable.tname=\"dr.chey\" and classtable.year==2016; task4: task5: task6: select avg(grade) from grade where classtable.cid=grade.cid having classname=\"is633\" and year=2016 groupby cid ; .

1. Problem 1. Please create the following tables with appropriate primary keys & foreign keys.
The list of tables is:
• Student table with 2 columns: sid (student ID), sname (student name).
• Teacher table with 2 columns: tid (teacher ID), tname (teacher name)
• Class table with 6 columns: cid (class ID), cname (class name), year (year of class), semester
(semester of class, e.g., fall, spring), credit (number of credits), tid (teacher ID).
• Grades table with 3 columns: sid (student ID), cid (class ID), grade (grade, 4 is A, 3 is B, 2 is
C, 1 is D, 0 is F).
Problem 2. Insert at least three rows of data to each table. Make sure you keep the primary key
and foreign key constraints.
Problem 3. Please write ONE SQL statement for each of the following tasks using tables created
in Problem 1.
Task 1: Return the total number of students
Task 2: Return the names of classes offered in Spring 2016 (spring is semester, 2016 is year).
Task 3: Return the names of classes taught by Dr. Chen in 2016.
Task 4: Return the IDs of classes with at least 2 students taking the class.
Task 5: Return the names of students who ever took Dr. Chen’s classes.
Task 6: Return the average grade of class IS 633 offered in spring 2016.
Solution
studenttable

2. sid            sname
10Â Â Â Â Â Â Â Â Â Â Â Â Â pavan
20Â Â Â Â Â Â Â Â Â Â Â Â Â sai
30Â Â Â Â Â Â Â Â Â Â Â Â praveen
teachertable:
tid      tname
11Â Â Â Â Â Â Â ravi
12Â Â Â Â Â Â Â samba
13Â Â Â Â Â Â Â murthy
classtable
cid       cname     year      semster  credit      tid
22          saint         Â
2016       2             a        11
23          mort          2015      Â
1            b        12
grade
sid  cid    grade
10Â Â 22Â Â Â Â Â Â Â Â a
20Â Â 23Â Â Â Â Â Â Â Â b
task1: select * from studenttable;
task2:select * from classtable where year=2016;
task3:select cname from classtable where teachertable.tid =classtable.tid and
teachertable.tname="dr.chey" and classtable.year==2016;
task4:
task5:

3. task6: select avg(grade) from grade
where classtable.cid=grade.cid
having classname="is633" and year=2016 groupby cid ;