SQL for balance due without grouping all select - sql

Question

I've provided a summary of my tables and I've gotten a good start on the SQL, but I'm stuck on figuring out how to limit how many items are returned. I should be able to choose one or more terms, and get back the balance due from just those terms.
A student should have 1 record, they can have several reservations over several terms, but payment is not specific to the reservation but rather to the student. That is the part that is throwing me off.
Table structure, date and the start of my SQL follow. Can someone help me with it please? This result should not be showing the $500 payment from term 3 for Sue Smith.
I'm using PostgreSQL, but I think this is a pretty basic question that doesn't require anything specific to Postgres.
Current result set:
Student ID Last First Total Fees Reservation Count Amount Paid Amount Due
123456 Jones Amy 50 1 50 0
412365 Smith Sue 100 3 545 -445
741258 Anderson Jon 50 1 0.00 50.00
963258 Holmes Fred 100 2 30 70
The schema:
SET search_path TO temp, public;
CREATE TABLE term
(term_id SERIAL PRIMARY KEY,
term_title VARCHAR(100));
CREATE TABLE student
(student_id SERIAL PRIMARY KEY,
student_sis_id VARCHAR(15),
student_first_name VARCHAR(30),
student_last_name VARCHAR(100));
CREATE TABLE reservation
(reservation_id SERIAL PRIMARY KEY,
student_id INTEGER REFERENCES student ON UPDATE CASCADE,
term_id INTEGER REFERENCES term ON UPDATE CASCADE,
reservation_fee_amount NUMERIC DEFAULT 0.00);
CREATE TABLE payment
(payment_id SERIAL PRIMARY KEY,
student_id INTEGER REFERENCES student ON UPDATE CASCADE,
term_id INTEGER REFERENCES term ON UPDATE CASCADE,
payment_cash_amount NUMERIC,
payment_credit_card_amount NUMERIC,
payment_check_amount NUMERIC);
INSERT INTO term VALUES (DEFAULT, 'SESSION 1');
INSERT INTO term VALUES (DEFAULT, 'SESSION 2');
INSERT INTO term VALUES (DEFAULT, 'SESSION 3');
INSERT INTO student VALUES (DEFAULT, 412365, 'Sue', 'Smith');
INSERT INTO student VALUES (DEFAULT, 123456, 'Amy', 'Jones');
INSERT INTO student VALUES (DEFAULT, 741258, 'Jon', 'Anderson');
INSERT INTO student VALUES (DEFAULT, 963258, 'Fred', 'Holmes');
INSERT INTO reservation VALUES (DEFAULT, 1, 1, 50);
INSERT INTO reservation VALUES (DEFAULT, 1, 2, 50);
INSERT INTO reservation VALUES (DEFAULT, 2, 1, 50);
INSERT INTO reservation VALUES (DEFAULT, 3, 2, 50);
INSERT INTO reservation VALUES (DEFAULT, 4, 1, 50);
INSERT INTO reservation VALUES (DEFAULT, 4, 2, 50);
INSERT INTO reservation VALUES (DEFAULT, 1, 3, 50);
INSERT INTO payment VALUES (DEFAULT, 1, 1, 25, 0, 0);
INSERT INTO payment VALUES (DEFAULT, 1, 1, 0, 20, 0);
INSERT INTO payment VALUES (DEFAULT, 2, 1, 25, 25, 0);
INSERT INTO payment VALUES (DEFAULT, 4, 1, 10, 10, 10);
INSERT INTO payment VALUES (DEFAULT, 1, 3, 500, 0, 0);
The query:
SELECT
student.student_sis_id AS "Student ID",
student.student_last_name AS Last,
student.student_first_name AS First,
SUM(reservation.reservation_fee_amount) AS "Total Fees",
(
SELECT COUNT(reservation.reservation_id)
FROM reservation
WHERE student.student_id = reservation.student_id
) AS "Reservation Count",
(
SELECT
COALESCE(SUM(
payment.payment_check_amount
+ payment.payment_cash_amount
+ payment.payment_credit_card_amount
), 0.00)
FROM payment
WHERE payment.student_id = student.student_id
) AS "Amount Paid",
SUM(reservation.reservation_fee_amount) - (
SELECT
COALESCE(SUM(
payment.payment_check_amount
+ payment.payment_cash_amount
+ payment.payment_credit_card_amount
), 0.00)
FROM payment WHERE payment.student_id = student.student_id
) AS "Amount Due"
FROM
student
INNER JOIN reservation ON student.student_id = reservation.student_id
WHERE reservation.term_id IN (1,2)
GROUP BY
student.student_id,
student.student_sis_id,
student.student_last_name,
student.student_first_name
ORDER BY
student.student_sis_id
;

Answer 1

Here is my updated version of the query:
SELECT
s.student_sis_id AS "Student ID",
s.student_last_name AS Last,
s.student_first_name AS First,
SUM(r.reservation_fee_amount) AS "Total Fees",
COUNT(r.reservation_id) AS "Reservation Count",
COALESCE(
SUM(
p.payment_check_amount
+ p.payment_cash_amount
+ p.payment_credit_card_amount
), 0.00
) AS "Amount Paid",
SUM(r.reservation_fee_amount) - (
COALESCE(
SUM(
p.payment_check_amount
+ p.payment_cash_amount
+ p.payment_credit_card_amount
), 0.00
)
) AS "Amount Due"
FROM
student s
INNER JOIN reservation r ON s.student_id = r.student_id
LEFT JOIN payment p ON p.student_id = r.student_id AND p.term_id = r.term_id
WHERE r.term_id IN (1,2)
GROUP BY
s.student_id,
s.student_sis_id,
s.student_last_name,
s.student_first_name
ORDER BY
s.student_sis_id
;
Things to watch:
I included payments in the main (outer) query in order to avoid subqueries
the join type is LEFT [OUTER] JOIN, so the lack of any payment rows will not prevent other data from appearing in the result set
the join condition includes term_id (basically this was the point where you were lost, I think)
and finally I used short table aliases for improving readability.
I hope this is what you are after.

Answer 2

Found the solution to the 2 payment entry problem (that I didn't recognize in my original question). Here is the answer:
set search_path to temp, public;
SELECT
s.student_sis_id AS "Student ID",
s.student_last_name AS "Last Name",
s.student_first_name AS "First Name",
SUM(r.reservation_fee_amount) AS "Total Fees",
COALESCE(p.paid, 0.00) AS "Amount Paid",
COALESCE(SUM(r.reservation_fee_amount) - p.paid, 0.00) AS "Amount Due"
FROM
student s
INNER JOIN reservation r ON s.student_id = r.student_id
left outer join
(
select student_id, term_id,
SUM(
p.payment_check_amount
+ p.payment_cash_amount
+ p.payment_credit_card_amount
) AS "paid"
from payment p
group by student_id, term_id
) as p
ON p.student_id = r.student_id AND p.term_id = r.term_id
WHERE r.reservation_completed AND r.term_id IN (1,2)
GROUP BY
s.student_sis_id,
s.student_last_name,
s.student_first_name,
p.paid
ORDER BY
s.student_sis_id
Thank you dezso and davek