使用 where in 条件从表中获取最新的 N 条记录

Question

Need to fetch the latest 3 records from tables of each orderid(s) related to storeid(s) using WHERE IN condition.

For Eg:

--------------------------
orderid      storeid
1               2
5               2
7               2
15              5
18              5
25              5
29              9
65              9
78              9
------------------------

Here my Query:

SELECT * FROM orders WHERE store_id IN('2', '5', '9') ORDER BY store_id

Thanks in advance.

Answer 1

using row_number() you can get the latest 3 orderids

select * from orders o
inner join (
   select row_number() over (partition by storeid order by orderid desc) rn, orderid 
   from orders) t1 on t1.orderid = o.orderid
where t1.rn <= 3

Answer 2

Here is the mysql solution to get n number of rows for each store:

SELECT
*
FROM
(
SELECT 
    store_id,
    order_id,
    @curRank := CASE WHEN @prevStore = store_id THEN @curRank + 1 ELSE 0 END AS rank,
    @prevStore:= store_id AS prevStore
FROM orders a, (SELECT @curRank := 0, @prevStore := NULL) r
WHERE store_id IN('2', '5', '9')
ORDER BY 1 desc,2
)a 

WHERE a.rank<3;