Top sales making product for each year - mysql

Question

I have two tables with following schema.
CREATE TABLE Product (
id INT AUTO_INCREMENT,
name VARCHAR(64) UNIQUE,
unit_price VARCHAR(6),
PRIMARY KEY (id)
);
CREATE TABLE Sale (
id INT AUTO_INCREMENT,
product_id INT, created_at DATETIME,
units INT, PRIMARY KEY (id),
FOREIGN KEY (product_id) REFERENCES Product(id)
);
INSERT INTO Product(name, unit_price)
VALUES
('Methadone', 30),
('Codeine', 20),
('Morphine', 40),
('Fentanyl', 10);
INSERT INTO Sale(product_id, created_at, units)
VALUES
(1, '2004-01-06 08:27:25', 8),
(4, '2004-03-05 05:21:15', 24),
(2, '2005-01-06 08:26:55', 3),
(4, '2005-03-31 01:55:25', 6),
(1, '2005-11-09 11:33:20', 2),
(4, '2006-02-15 10:46:30', 4),
(3, '2006-04-14 07:40:50', 1),
(4, '2008-01-06 08:27:25', 5),
(4, '2008-01-10 21:31:45', 3),
(1, '2008-01-28 16:07:30', 9),
(3, '2008-03-05 05:21:00', 4),
(2, '2008-03-08 18:25:50', 5),
(4, '2008-05-02 02:15:20', 1),
(4, '2008-05-05 15:19:40', 3),
(4, '2008-06-28 23:08:55', 2),
(4, '2008-07-02 12:14:00', 2),
(3, '2008-08-29 09:07:50', 1),
(2, '2008-10-22 16:56:20', 5),
(3, '2008-10-26 06:01:25', 2),
(4, '2008-12-19 13:49:55', 4),
(2, '2008-12-23 02:55:30', 4),
(1, '2009-02-15 10:43:45', 4),
(2, '2009-04-14 07:37:50', 6),
(3, '2009-06-11 04:31:25', 3),
(4, '2009-08-08 01:25:30', 12),
(1, '2010-11-09 11:33:20', 8),
(1, '2011-01-14 10:22:35', 3),
(3, '2011-03-13 07:16:10', 3),
(4, '2011-05-10 04:10:15', 4),
(4, '2011-07-07 01:04:35', 4),
(4, '2011-09-02 21:58:10', 3),
(2, '2011-10-30 18:51:45', 3),
(1, '2011-12-27 15:45:20', 1),
(4, '2012-02-23 12:43:25', 2),
(4, '2012-04-21 09:37:30', 3),
(4, '2012-06-18 06:31:20', 1),
(2, '2012-08-15 03:25:40', 4),
(2, '2013-01-14 10:23:20', 4),
(4, '2013-02-01 05:01:35', 1),
(4, '2013-03-13 07:16:55', 1),
(4, '2013-03-31 01:55:10', 2),
(4, '2013-05-10 04:11:15', 2),
(3, '2013-05-27 22:48:45', 3),
(1, '2013-07-07 01:05:20', 3),
(2, '2013-07-24 19:42:20', 4),
(4, '2013-09-02 21:59:40', 4),
(3, '2013-09-20 16:36:10', 1),
(4, '2013-10-30 18:54:00', 2),
(4, '2013-11-17 13:29:45', 1),
(4, '2013-12-27 15:48:20', 3);
I want to find top sales making product for each year sorted by year in descending order along-with the total sale made for the top selling product.
I have written the following query.
SELECT EXTRACT(YEAR FROM S.created_at) as year,
GROUP_CONCAT(DISTINCT P1.name
ORDER BY P1.name
SEPARATOR ',')as top,
MAX(S.units*P1.unit_price) as sale
FROM Sale S
INNER JOIN Product P1 ON S.product_id=P1.id
GROUP BY year
ORDER BY year desc
Expected Output:
2013 Codeine,Fentanyl,Morphine 160
2012 Codeine 80
2011 Methadone,Morphine 120
2010 Methadone 240
2009 Codeine,Fentanyl,Methadone,Morphine 120
2008 Codeine,Morphine 280
2006 Fentanyl,Morphine 40
2005 Codeine,Fentanyl,Methadone 60
2004 Fentanyl,Methadone 240
Original Output:
2013 Codeine,Fentanyl,Methadone,Morphine 120
2012 Codeine,Fentanyl 80
2011 Codeine,Fentanyl,Methadone,Morphine 120
2010 Methadone 240
2009 Codeine,Fentanyl,Methadone,Morphine 120
2008 Codeine,Fentanyl,Methadone,Morphine 270
2006 Fentanyl,Morphine 40
2005 Codeine,Fentanyl,Methadone 60
2004 Fentanyl,Methadone 240
The query was supposed to return only the top selling products, bu it's returning all the products. Could anyone provide any help?

Answer 1

Here is a solution for MySQL < 8.0. First, aggregate sales by year and product and filter on the top selling products with an aggregate, correlated subquery; then, aggregate by year:
select
year_at,
group_concat(name order by name) products,
total_sales
from (
select
year(s.created_at) year_at,
p.name,
sum(s.units * p.unit_price) total_sales
from Product p
inner join Sale s on s.product_id = p.id
group by year_at, p.id, p.name
having total_sales = (
select sum(s1.units * p1.unit_price) total_sales1
from Product p1
inner join Sale s1 on s1.product_id = p1.id
where year(s1.created_at) = year_at
group by s1.product_id
order by total_sales1 desc
limit 1
)
) t
group by year_at, total_sales
order by year_at desc
Demo on DB Fiddlde:
year_at | products | total_sales
------: | :---------------------------------- | ----------:
2013 | Codeine,Fentanyl,Morphine | 160
2012 | Codeine | 80
2011 | Methadone,Morphine | 120
2010 | Methadone | 240
2009 | Codeine,Fentanyl,Methadone,Morphine | 120
2008 | Codeine,Morphine | 280
2006 | Fentanyl,Morphine | 40
2005 | Codeine,Fentanyl,Methadone | 60
2004 | Fentanyl,Methadone | 240

Answer 2

You seem to be after this...
SELECT GROUP_CONCAT(a.name) names,a.total, a.year
FROM
( SELECT p.name
, SUM(p.unit_price*s.units) total
, YEAR(created_at) year
FROM product p
JOIN sale s
ON s.product_id = p.id
GROUP
BY year
, name
) a
JOIN
( SELECT MAX(total) total
, year
FROM
( SELECT p.name
, SUM(p.unit_price*s.units) total
, YEAR(created_at) year
FROM product p
JOIN sale s
ON s.product_id = p.id
GROUP
BY year
, name
) n
GROUP
BY year) b
ON b.year = a.year AND b.total = a.total
GROUP BY a.total, a.year
ORDER BY year DESC;
+-------------------------------------+-------+------+
| names | total | year |
+-------------------------------------+-------+------+
| Fentanyl,Codeine,Morphine | 160 | 2013 |
| Codeine | 80 | 2012 |
| Morphine,Methadone | 120 | 2011 |
| Methadone | 240 | 2010 |
| Morphine,Methadone,Fentanyl,Codeine | 120 | 2009 |
| Morphine,Codeine | 280 | 2008 |
| Morphine,Fentanyl | 40 | 2006 |
| Codeine,Methadone,Fentanyl | 60 | 2005 |
| Methadone,Fentanyl | 240 | 2004 |
+-------------------------------------+-------+------+

Answer 3

Here's a variant of my Scalar-Aggregate Comparison query technique that will achieve what you want in a vastly better-performing query than self-joining the aggregate results. As you can see below, this only ever performs a single join, then 3 cascaded layers of aggregation to achieve the final output.
SELECT
yr,
SUBSTRING(MAX(CONCAT(LPAD(total_sales, 16, '0'), products)), 17) AS best_seller,
MAX(total_sales) AS sales_amount
FROM (
SELECT
yr,
total_sales,
GROUP_CONCAT(name order by name) AS products
FROM (
SELECT
YEAR(s.created_at) AS yr,
p.id,
p.name,
SUM(s.units * p.unit_price) AS total_sales
FROM Product AS p
INNER JOIN Sale AS s on s.product_id = p.id
GROUP BY YEAR(s.created_at), p.id
) AS pys
GROUP BY yr, total_sales
) AS py
GROUP BY yr
ORDER BY yr DESC;
Here's a DB Fiddle demo: https://dbfiddle.uk/?rdbms=mysql_5.6&fiddle=e14ed7f396738ce064f1998bdb4310ac

Answer 4

try this:
Select name, year(created_at), sum(unit_price*units )
from Product p inner join sale s on p.id = s.product_id
group by name, year(created_at)
order by 2, 3 desc

Answer 5

If you want the top selling product for each year, use rank() and an aggregation query:
select ps.*
from (select p.name, year(s.created_at) as year, sum(p.unit_price*s.units) as sales
rank() over (partition by year(s.created_at) order by sum(p.unit_price*s.units) desc as seqnum
from Product p inner join
sale s
on p.id = s.product_id
group by name, year
) ps
where seqnum <= 1; -- You can change "1" for more rows