SQL null values not being shown in results - sql

Question

I'm having trouble getting the null values on a SQL Query. This is the description of the problem:
Gross income by week. Money is collected from guests when they leave.
For each Thursday in November and December 2016, show the total amount
of money collected from the previous Friday to that day, inclusive.
Here's the code that I've written that should return the weekly income from Thursday to previous Friday, the answer i get is partially correct as the weeks that have income are correctly displayed while the weeks that don't have any income are not displayed. I've tried adding a IFNULL clause but that's still not fixing the problem.
SELECT DATE_ADD(MAKEDATE(2016, 7), INTERVAL WEEK(DATE_ADD(calendar.i, INTERVAL booking.nights - 5 DAY), 0) WEEK) AS Thursday, IFNULL(SUM(booking.nights * rate.amount) + SUM(e.amount),0) AS weekly_ncome
FROM booking
RIGHT OUTER
JOIN calendar ON booking.booking_date = calendar.i
JOIN rate ON (booking.occupants = rate.occupancy AND booking.room_type_requested = rate.room_type)
LEFT JOIN (
SELECT booking_id, IFNULL(SUM(amount),0) AS amount
FROM extra
GROUP BY booking_id
) AS e ON (e.booking_id = booking.booking_id)
GROUP BY Thursday;
For reference, this is a question found on SQLzoo Guesthouse section, question 15. This is the expected result:
+------------+---------------+
| Thursday | weekly_income |
+------------+---------------+
| 2016-11-03 | 0.00 |
| 2016-11-10 | 12608.94 |
| 2016-11-17 | 13552.56 |
| 2016-11-24 | 12929.69 |
| 2016-12-01 | 11685.14 |
| 2016-12-08 | 13093.79 |
| 2016-12-15 | 8975.87 |
| 2016-12-22 | 1395.77 |
| 2016-12-29 | 0.00 |
| 2017-01-05 | 0.00 |
+------------+---------------+
I get the same as above but the ones with weekly income of 0 don't show up.

Answer 1

Here is one way to get the Thursdays in Nov 2016 and Dec 2016:
SELECT i AS thursday, i - INTERVAL 6 DAY AS friday
FROM calendar
WHERE i >= '2016-11-01' AND i - INTERVAL 6 DAY <= '2016-12-31' AND DAYOFWEEK(i) = 5
Just left join your data with this, make sure that you join with the checkout date (booking_date + nights days):
SELECT
thursday, SUM(
COALESCE(booking.nights * rate.amount, 0) +
COALESCE(extras.total, 0)
) AS weekly_income
FROM (
SELECT i AS thursday, i - INTERVAL 6 DAY AS friday
FROM calendar
WHERE i >= '2016-11-01' AND i - INTERVAL 6 DAY <= '2016-12-31' AND DAYOFWEEK(i) = 5
) AS thursdays
LEFT JOIN (
booking
INNER JOIN rate ON booking.occupants = rate.occupancy AND booking.room_type_requested = rate.room_type
LEFT JOIN (
SELECT booking_id, SUM(amount) AS total
FROM extra
GROUP BY booking_id
) AS extras ON booking.booking_id = extras.booking_id
) ON booking.booking_date + INTERVAL booking.nights DAY BETWEEN friday AND thursday
GROUP BY thursday