Sales SUM per country, state, city and district from five Mysql tables - php

Question

I have the five below tables, I want to show the sales SUM per country, state, city and district by using one mysql query if possible:
note: If there is no sales in the state, city, district, then I need the query result to show 0 or empty space (the state, city, district name has to be shown even if there is no sales for that specific state, city or district)
+------------+----------+
| country |
+------------+----------+
| country_id | country |
+------------+----------+
| 1 | country1 |
| 2 | country2 |
+------------+----------+
+----------------+--------+------------+
| state_province |
+----------------+--------+------------+
| state_id | state | country_id |
+----------------+--------+------------+
| 1 | state1 | 1 |
| 2 | state1 | 2 |
| 3 | state2 | 2 |
| 4 | state2 | 1 |
+----------------+--------+------------+
+---------+-------+----------+
| city |
+---------+-------+----------+
| city_id | city | state_id |
+---------+-------+----------+
| 1 | city1 | 1 |
| 2 | city2 | 1 |
| 3 | city1 | 3 |
| 4 | city2 | 3 |
| 5 | city1 | 4 |
| 6 | city2 | 4 |
+---------+-------+----------+
please note that state (state_id =2) in country (country_id = 2) has no cities in the above table.
+-------------+-----------+---------+
| district |
+-------------+-----------+---------+
| district_id | district | city_id |
+-------------+-----------+---------+
| 1 | district1 | 1 |
| 2 | district2 | 1 |
| 3 | district1 | 2 |
| 4 | district2 | 2 |
| 5 | district1 | 4 |
| 6 | district2 | 4 |
| 7 | district1 | 5 |
| 8 | district1 | 6 |
+-------------+-----------+---------+
+----------+------------+----------+---------+-------------+--------+
| sales |
+----------+------------+----------+---------+-------------+--------+
| sales_id | country_id | state_id | city_id | district_id | amount |
+----------+------------+----------+---------+-------------+--------+
| 1 | 1 | 0 | 0 | 0 | 1000 |
| 2 | 1 | 0 | 0 | 0 | 2000 |
| 3 | 1 | 1 | 0 | 0 | 300 |
| 4 | 1 | 1 | 0 | 0 | 70 |
| 5 | 1 | 1 | 1 | 0 | 50 |
| 6 | 1 | 1 | 1 | 1 | 25 |
| 7 | 1 | 4 | 1 | 1 | 25 |
| 8 | 1 | 4 | 5 | 0 | 25 |
| 9 | 2 | 0 | 0 | 0 | 3000 |
| 10 | 2 | 0 | 0 | 0 | 500 |
| 11 | 2 | 3 | 0 | 0 | 300 |
| 12 | 2 | 3 | 4 | 6 | 70 |
+----------+------------+----------+---------+-------------+--------+
Demo with my current attempt
Thank you

Answer 1

If you want to group by three column (city_id, state_id, district_id), it's pointless, since it won't change anything in your sales table. There you have already partitoned information.
Moreover, in sales table you have 0 in place of some IDs and there isn't any ID equal to 0 in any table. You need to rethink what you really want I guess.
I think you just need simple JOIN:
SELECT country,
state,
city,
district,
coalesce(amount, 0) amount
FROM country ctr
JOIN state_province st ON ctr.country_id = st.country_id
JOIN city c ON c.state_id = st.state_id
LEFT JOIN district d ON d.city_id = c.city_id
LEFT JOIN sales s ON
s.country_id = ctr.country_id AND
s.state_id = st.state_id AND
s.city_id = c.city_id AND
s.district_id = d.district_id
Demo