Using two aggregate function - min and max on same query - sql

Question

Here is my product table's data -
product_id category discount
454 C-10 10
357 C-10 9
64 C-10 10
294 C-11 17
449 C-11 17
471 C-11 17
89 C-11 12
56 C-11 10
I want to get the max discount for every product category and if any category has multiple products having same discount, the product having the minimum
product_id should be selected.
Desired output -
product_id category discount
64 C-10 10
294 C-11 17
I tried below two query but not working -
select category,min(product_id),max(discount)
from Product
group by category
Your help is very much appreciated. Thanks!

Answer 1

Using ROW_NUMBER is helpful here:
WITH cte AS (
SELECT product_id, category, discount,
ROW_NUMBER() OVER (PARTITION BY category
ORDER BY discount DESC, product_id) rn
FROM Product
)
SELECT product_id, category, discount
FROM cte
WHERE rn = 1;
Or, we could even do this without using a subquery/CTE:
SELECT TOP 1 WITH TIES product_id, category, discount
FROM Product
ORDER BY
ROW_NUMBER() OVER (PARTITION BY category
ORDER BY discount DESC, product_id);

Answer 2

use row_number()
select * from
(
select *,row_number() over(partition by category order by discount desc, poroduct_id asc) rn
from tablename
)A where rn=1
OR
use correlated subquery
select * from tablename a where discount in
(select max(discount) from tablename b where a.category=b.category
having min(b.product_id)=a.product_id)

Answer 3

use outer apply
with cte as
(
select 454 as product_id, 'C-10' as category, 10 as discount union all
select 357,'C-10',9 union all
select 64,'C-10',10 union all
select 294,'C-11',17 union all
select 449,'C-11',17 union all
select 471,'C-11',17 union all
select 89,'C-11', 12 union all
select 56,'C-11', 10
) select distinct p1.category,a.product_id,a.discount
from cte p1
outer apply ( select top 1 p2.*
from cte p2 where p1.category=p2.category
order by discount desc, product_id asc
) a
output
category product_id discount
C-10 64 10
C-11 294 17
demo link