How to create a SQL query for the below scenario - sql

Question

I am using Snowflake SQL, but I guess this can be solved by any sql. So I have data like this:
RA_MEMBER_ID YEAR QUARTER MONTH Monthly_TOTAL_PURCHASE CATEGORY
1000 2020 1 1 105 CAT10
1000 2020 1 1 57 CAT13
1000 2020 1 2 107 CAT10
1000 2020 1 2 59 CAT13
1000 2020 1 3 109 CAT11
1000 2020 1 3 61 CAT14
1000 2020 2 4 111 CAT11
1000 2020 2 4 63 CAT14
1000 2020 2 5 113 CAT12
1000 2020 2 5 65 CAT15
1000 2020 2 6 115 CAT12
1000 2020 2 6 67 CAT15
And I need data like this:
RA_MEMBER_ID YEAR QUARTER MONTH Monthly_TOTAL_PURCHASE CATEGORY Monthly_rank Quarterly_Total_purchase Quarter_category Quarter_rank Yearly_Total_purchase Yearly_category Yearly_rank
1000 2020 1 1 105 CAT10 1 105 CAT10 1 105 CAT10 1
1000 2020 1 1 57 CAT13 2 57 CAT13 2 57 CAT13 2
1000 2020 1 2 107 CAT10 1 212 CAT10 1 212 CAT10 1
1000 2020 1 2 59 CAT13 2 116 CAT13 2 116 CAT13 2
1000 2020 1 3 109 CAT11 1 212 CAT10 1 212 CAT10 1
1000 2020 1 3 61 CAT14 2 116 CAT13 2 116 CAT13 2
1000 2020 2 4 111 CAT11 1 111 CAT11 1 212 CAT10 1
1000 2020 2 4 63 CAT14 2 63 CAT14 2 124 CAT14 2
1000 2020 2 5 113 CAT12 1 113 CAT12 1 212 CAT10 1
1000 2020 2 5 65 CAT15 2 65 CAT15 2 124 CAT14 2
1000 2020 2 6 115 CAT12 1 228 CAT12 1 228 CAT12 1
1000 2020 2 6 67 CAT15 2 132 CAT15 2 132 CAT15 2
So basically, I have the top two categories by purchase amount for the first 6 months. I need the same for quarterly based on which month of the quarter it is. So let's say it is February, then the top 2 categories and amounts should be calculated based on both January and February. For March we have to get the quarter data by taking all three months. From April it will be the same as monthly rank, for May again calculate based on April and May. Similarly for Yearly also.
I have tried a lot of things but nothing seems to give me what I want.
The solution should be generic enough because there can be many other months and years.
I really need help in this.

Answer 1

Not sure if below is what you are after. I assume that everything is category based:
create or replace table test (
ra_member_id int,
year int,
quarter int,
month int,
monthly_purchase int,
category varchar
);
insert into test values
(1000, 2020, 1,1, 105, 'cat10'),
(1000, 2020, 1,1, 57, 'cat13'),
(1000, 2020, 1,2, 107, 'cat10'),
(1000, 2020, 1,2, 59, 'cat13'),
(1000, 2020, 1,3, 109, 'cat11'),
(1000, 2020, 1,3, 61, 'cat14'),
(1000, 2020, 2,4, 111, 'cat11'),
(1000, 2020, 2,4, 63, 'cat14'),
(1000, 2020, 2,5, 113, 'cat12'),
(1000, 2020, 2,5, 65, 'cat15'),
(1000, 2020, 2,6, 115, 'cat12'),
(1000, 2020, 2,6, 67, 'cat15');
WITH BASE as (
select
RA_MEMBER_ID,
YEAR,
QUARTER,
MONTH,
CATEGORY,
MONTHLY_PURCHASE,
LAG(MONTHLY_PURCHASE) OVER (PARTITION BY QUARTER, CATEGORY ORDER BY MONTH) AS QUARTERLY_PURCHASE_LAG,
IFNULL(QUARTERLY_PURCHASE_LAG, 0) + MONTHLY_PURCHASE AS QUARTERLY_PURCHASE,
LAG(MONTHLY_PURCHASE) OVER (PARTITION BY YEAR, CATEGORY ORDER BY MONTH) AS YEARLY_PURCHASE_LAG,
IFNULL(YEARLY_PURCHASE_LAG, 0) + MONTHLY_PURCHASE AS YEARLY_PURCHASE
FROM
TEST
),
BASE_RANK AS (
SELECT
RA_MEMBER_ID,
YEAR,
QUARTER,
MONTH,
CATEGORY,
MONTHLY_PURCHASE,
RANK() OVER (PARTITION BY MONTH ORDER BY MONTHLY_PURCHASE DESC) as MONTHLY_RANK,
QUARTERLY_PURCHASE,
RANK() OVER (PARTITION BY QUARTER ORDER BY QUARTERLY_PURCHASE DESC) as QUARTERLY_RANK,
YEARLY_PURCHASE,
RANK() OVER (PARTITION BY YEAR ORDER BY YEARLY_PURCHASE DESC) as YEARLY_RANK
FROM BASE
),
MAIN AS (
SELECT
RA_MEMBER_ID,
YEAR,
QUARTER,
MONTH,
CATEGORY,
MONTHLY_PURCHASE,
MONTHLY_RANK,
QUARTERLY_PURCHASE,
QUARTERLY_RANK,
YEARLY_PURCHASE,
YEARLY_RANK
FROM BASE_RANK
)
SELECT * FROM MAIN
ORDER BY YEAR, QUARTER, MONTH
;
Result:
+--------------+------+---------+-------+----------+------------------+--------------+--------------------+----------------+-----------------+-------------+
| RA_MEMBER_ID | YEAR | QUARTER | MONTH | CATEGORY | MONTHLY_PURCHASE | MONTHLY_RANK | QUARTERLY_PURCHASE | QUARTERLY_RANK | YEARLY_PURCHASE | YEARLY_RANK |
|--------------+------+---------+-------+----------+------------------+--------------+--------------------+----------------+-----------------+-------------|
| 1000 | 2020 | 1 | 1 | cat10 | 105 | 1 | 105 | 4 | 105 | 9 |
| 1000 | 2020 | 1 | 1 | cat13 | 57 | 2 | 57 | 6 | 57 | 12 |
| 1000 | 2020 | 1 | 2 | cat10 | 107 | 1 | 212 | 1 | 212 | 3 |
| 1000 | 2020 | 1 | 2 | cat13 | 59 | 2 | 116 | 2 | 116 | 6 |
| 1000 | 2020 | 1 | 3 | cat11 | 109 | 1 | 109 | 3 | 109 | 8 |
| 1000 | 2020 | 1 | 3 | cat14 | 61 | 2 | 61 | 5 | 61 | 11 |
| 1000 | 2020 | 2 | 4 | cat11 | 111 | 1 | 111 | 4 | 220 | 2 |
| 1000 | 2020 | 2 | 4 | cat14 | 63 | 2 | 63 | 6 | 124 | 5 |
| 1000 | 2020 | 2 | 5 | cat12 | 113 | 1 | 113 | 3 | 113 | 7 |
| 1000 | 2020 | 2 | 5 | cat15 | 65 | 2 | 65 | 5 | 65 | 10 |
| 1000 | 2020 | 2 | 6 | cat12 | 115 | 1 | 228 | 1 | 228 | 1 |
| 1000 | 2020 | 2 | 6 | cat15 | 67 | 2 | 132 | 2 | 132 | 4 |
+--------------+------+---------+-------+----------+------------------+--------------+--------------------+----------------+-----------------+-------------+