Select 5 latest rows of each column pair

Question

I've got a big table (>1m. rows) with a structure similar to this one:

ID	foreign_key_1	foreign_key_2	clicks	installs	created_at
1	01	01	2	0	2022-11-10
2	01	02	54	12	2022-11-10
3	01	01	9	0	2022-11-11
4	01	02	85	20	2022-11-11
5	01	01	3	1	2022-11-12
6	01	02	8	0	2022-11-12
7	01	01	6	0	2022-11-13
8	01	02	221	60	2022-11-13
9	01	01	61	10	2022-11-14
10	01	02	75	17	2022-11-14
11	01	01	58	8	2022-11-15
12	01	02	9	0	2022-11-15
13	01	01	10	1	2022-11-16
14	01	02	25	0	2022-11-16

How would I be able to select the latest 5 rows of every unique pair of foreign_key_1 and foreign_key_2, based on their created_at dates? And is that even possible?

I've tried experimenting with partitions and grouping but I'm a begginer at writing mySQL syntax and complex queries so I haven't been able to figure it out.

Answer 1

One possible solution would be to use the row_number() window function where you partition by foreign_key_1 and foreign_key_2, and order the partitions by created_at in descending order:

with row_nums as (
  select
    *,
    row_number() over (
      partition by foreign_key_1, foreign_key_2 order by created_at desc
    ) as rn
  from your_table
)

select *
from row_nums
where rn <= 5