Finding rows with latest date by id mysql - mysql

Question

I have these 2 tables I am trying to write a query that will help me select all rows that gives this result
users
id
name
1
test
2
test2
logs
id
userId
message
date
1
1
this is a test
2020-10-07 12:57:14
2
1
another reason
2020-10-07 13:57:14
3
1
another reason 2
2020-10-07 14:57:14
4
2
another reason 3
2020-10-04 12:57:14
5
2
another reason 4
2020-10-05 12:57:14
6
2
another reason 4
2020-10-06 12:57:14
Output Table
I need to pass many user Ids like in this case (1,2) and get below table only return MAX (date) per row per userId
id
userId
message
date
3
1
another reason 2
2020-10-07 14:57:14
6
2
another reason 4
2020-10-06 12:57:14
Is this possible with one Query? This what I have but not working
SELECT
id ,
userId ,
message,
date
FROM logs
WHERE userId IN (1,2)
ORDER BY date DESC;

Answer 1

You may use the results of a window function ROW_NUMBER to retrieve these results.
SELECT
id,userId,message,date
FROM (
SELECT
*,
ROW_NUMBER() OVER (
PARTITION BY userId
ORDER BY date DESC
) as rn
FROM
logs
) t
WHERE rn=1 AND
userId IN (1,2)
ORDER BY date DESC
and for older mysql versions
SELECT
id,userId,message,date
FROM (
SELECT
l.*,
#row_num:=IF(userId=#prev_user_id,#row_num+1,1) as rn,
#prev_user_id:=userId
FROM
logs l
CROSS JOIN (
SELECT #row_num:=0, #prev_user_id:=NULL
) as vars
ORDER BY userId, date DESC
) t
WHERE rn=1 AND
userId IN (1,2)
ORDER BY date DESC