Case, group by , join on multiple table - mysql

Question

I have 3 tables transaction , store and date. A column in store table needs to be assigned values based on conditions and that new column needs to be used in group by.
ASK is to find ` total sales across different banners for a particular time period.
i am using following query..
"""select sum(net_spend) as sales , d.fis_week_id, st.banner
from ( select s*,
CASE WHEN st.format IN ('S','S MINI','S HYPER') THEN 'S'
WHEN st.format = 'CHECKERS' THEN 'CHECKERS'
ELSE st.format END AS banner
from store_dim s) st
from transaction_item_fct tr
inner join date_dim d on d.date_id = tr.date_id
inner join store_dim_c s on st.store_id = tr.store_id
where d.fis_week_id >=201809 and d.fis_week_id<=201813
and tr.store_id = st.store_id
group by st.banner, d.fis_week_id
"""
Where I am getting wrong?
Below is the fabricated tables' data
Transaction table-
store_id week_id net_spend
1 12 345
1 11 788
2 13 556
3 11 300
Store table
store_id format
1 S
2 S MINI
3 S Hyper
4 Checker
Date table
week_id fis_week_id
11 201712
12 201717
Result expected is
week_id banner spend
11 S 888
11 Hyper 666

Answer 1

It's not 100% clear from your question but I think this query will do what you want. You will need to change the WHERE condition on d.fis_week_id as appropriate for your needs, I have made it appropriate for the demo case I set up.
SELECT d.week_id, st.banner, SUM(t.net_spend) AS sales, d.fis_week_id
FROM date_dim d
LEFT JOIN transaction_item t ON t.week_id = d.week_id
JOIN (SELECT store_id,
CASE WHEN format IN ('S', 'S MINI', 'S Hyper') THEN 'S'
WHEN format = 'Checker' THEN 'Checker'
ELSE format
END AS banner
FROM store_dim s) st
ON st.store_id = t.store_id
WHERE d.fis_week_id BETWEEN 201712 AND 201720
GROUP BY d.week_id, st.banner
I've expanded your demo data out a bit and created a test case at SQLFiddle:
CREATE TABLE transaction_item
(`store_id` int, `week_id` int, `net_spend` int);
INSERT INTO transaction_item
(`store_id`, `week_id`, `net_spend`)
VALUES (1, 12, 345), (1, 11, 788), (2, 13, 556), (3, 11, 300),
(4, 11, 440), (4, 12, 123), (5, 11, 100), (6, 13, 444);
CREATE TABLE store_dim
(`store_id` int, `format` varchar(7));
INSERT INTO store_dim
(`store_id`, `format`)
VALUES (1, 'S'), (2, 'S MINI'), (3, 'S Hyper'), (4, 'Checker'), (5, 'Checker'), (6, 'Other');
CREATE TABLE date_dim
(`week_id` int, `fis_week_id` int);
INSERT INTO date_dim
(`week_id`, `fis_week_id`)
VALUES (11, 201712), (12, 201717), (13, 201720);
Output:
week_id banner sales fis_week_id
11 Checker 540 201712
11 S 1088 201712
12 Checker 123 201717
12 S 345 201717
13 Other 444 201720
13 S 556 201720