cmkl/fall-2025/sen-209/labs/Session3/commands/PostgreSQL commands.md

1022 B

SEN-209: Lab 3 - ERD & SQL CRUD

Insert 3 students and 2 courses

INSERT INTO students VALUES (1000, 'Peter', 'Parker', '2001-08-10'), (1001, 'Miles', 'Morales', '2001-08-03'), (1002, 'Gwen', 'Stacy', '2001-04-18');

INSERT INTO courses VALUES ('2sf3Lf', 'Physics I', 5), ('XjxDA6', 'Chemistry I', 6),

Enroll students into courses with grades

INSERT INTO enrollment VALUES (1000, 'XjxDA6', 'A'), (1000, '2sf3Lf', 'A+'), (1001, '2sf3Lf', 'B'), (1002, 'XjxDA6', 'A'), (1002, '2sf3Lf', 'A+');

Retrieve all students with their enrolled courses

SELECT st.fname, st.lname, STRING_AGG ( c.cName, ',' ) enrolled FROM students st INNER JOIN enrollment e ON e.sID = st.sID INNER JOIN courses c ON c.cID = e.cID GROUP BY st.fname, st.lname;

Update one student's grade

UPDATE enrollment SET grade = 'A' WHERE sID = 1001 AND cID = '2sf3Lf';

Delete one enrollment record

DELETE FROM enrollment WHERE sID = 1002 AND cID = 'XjxDA6';