Aggregating query on Table? - mysql

Question

I am stuck in one point i have to pick the data from the customer table which has values of customer_id and amount_paid . I want to show a result in the form that first 3 values of the user should be visible in a column name group as a text Group1 and 4 to 10 values of that user to get text Group2 and rest Group3 .
Can you please tell me how to group the values for every customer ?
Thanks

Answer 1

I want to show a result in the form that first 3 values of the user should be visible in a column name group as a text Group1 and 4 to 10 values of that user to get text Group2 and rest Group3
Below is for BigQuery Standard SQL
#standardSQL
SELECT
user_id,
CASE
WHEN pos BETWEEN 1 AND 3 THEN 1
WHEN pos BETWEEN 4 AND 10 THEN 2
ELSE 3
END grp,
SUM(amount_paid) amount_paid
FROM (
SELECT
user_id, amount_paid,
ROW_NUMBER() OVER(PARTITION BY user_id ORDER BY amount_paid DESC) pos
FROM customer
)
GROUP BY user_id, grp
-- ORDER BY user_id, grp
You can test / play with below dummy generated data
#standardSQL
WITH users AS (
SELECT user_id FROM UNNEST(GENERATE_ARRAY(1,5)) user_id
),
amounts AS (
SELECT ROUND(50 * RAND()) amount_paid FROM UNNEST(GENERATE_ARRAY(1,50)) amount_paid
),
customer AS (
SELECT user_id, ROUND(amount_paid * RAND()) amount_paid
FROM users
CROSS JOIN amounts
)
SELECT
user_id,
CASE
WHEN pos BETWEEN 1 AND 3 THEN 1
WHEN pos BETWEEN 4 AND 10 THEN 2
ELSE 3
END grp,
SUM(amount_paid) amount_paid
FROM (
SELECT
user_id, amount_paid,
ROW_NUMBER() OVER(PARTITION BY user_id ORDER BY amount_paid DESC) pos
FROM customer
)
GROUP BY user_id, grp
ORDER BY user_id, grp
The output will look like below
user_id grp amount_paid
1 1 147.0
1 2 323.0
1 3 879.0
2 1 147.0
2 2 323.0
2 3 879.0
. . .
so you still need calculate share which (from your question and hopefully) is not a problem for you
added share calculation
#standardSQL
WITH grps AS (
SELECT
user_id,
CASE
WHEN pos BETWEEN 1 AND 3 THEN 1
WHEN pos BETWEEN 4 AND 10 THEN 2
ELSE 3
END grp,
SUM(amount_paid) amount_paid
FROM (
SELECT
user_id, amount_paid,
ROW_NUMBER() OVER(PARTITION BY user_id ORDER BY amount_paid DESC) pos
FROM customer
)
GROUP BY user_id, grp
)
SELECT * ,
ROUND(amount_paid / SUM(amount_paid) OVER(PARTITION BY user_id), 3) share
FROM grps
-- ORDER BY user_id, grp