Get the first n lines for group after summing up - mysql

Question

I am practising my skills in MySQL using the Sakila DB.
I would I have created a view called rentals_customer_store_film_category with is the union of customers, payments, rentals, film, and category tables.
I would now like to get the top 5 films by income. Meaning that I would lie to sum up all incomes of each film by store and then return the first 5.
I tried the below code but it does not work.
I cannot figure out what is wrong with it
Any help?
SELECT store_id, film_id, income
FROM
(SELECT film_id, store_id, sum(amount) as income,
#store_rank := IF(#current_store = store_id, #store_rank + 1, 1) AS store_rank,
#current_store := store_id
FROM rentals_customer_store_film_category
group by store_id, film_id
ORDER BY store_id, income DESC, film_id
) ranked
WHERE store_rank <= 5
RESULTS BELOW. As you can see, it does not stop at the fifth row per store. It shows all films by store while I would like only the top 5 for store:id 1 and top 5 for store id 2.
store_id film_id income
1 971 134.82
1 879 132.85
1 938 127.82
1 973 123.83
1 865 119.84
1 941 117.82
1 267 116.83
1 327 110.85
1 580 106.86
1 715 105.85
1 897 104.85
...
...
...
...
2 878 127.83
2 791 127.82
2 854 123.83
2 946 117.86
2 396 113.81
2 369 111.84
2 764 110.85
2 260 110.84
2 838 110.82
2 527 109.83
2 893 106.84
2 71 102.87
2 8 102.82
...
...
...
...

Answer 1

The order in this case is important to compare the previous store_id with the current,try this:
SELECT store_id, film_id, income
FROM
(SELECT film_id, store_id, sum(amount) as income,
#First compare previus with current
#store_rank := IF(#prev_store = store_id, #store_rank + 1, 1) AS store_rank,
#asign previus store
#prev_store := store_id
FROM films
group by store_id, film_id
ORDER BY store_id, income DESC, film_id
) ranked
WHERE store_rank <= 5