Sqlserver predict top5 records but various group - mathematical logic - sql-server

Question

I have table like below,
user_id Task_name Score
__________________________________
1 101 10
1 102 9
1 103 8
2 104 10
2 105 9
3 106 9
4 107 9
4 108 8
5 109 8
5 110 7
5 111 6
6 112 10
6 113 9
6 114 8
7 115 9
7 116 8
I want to take top 5 score or max 5 Tasks.
Condition:
1) At least try to get one Tasks from one user.
Output:
User_Id Task_Name Score
____________________________________
1 101 10
2 104 10
6 112 10
3 106 9
4 107 9

Answer 1

I think this is what you need:
SELECT TOP 5 User_id, Task_name, Score
FROM
(
SELECT *, ROW_NUMBER() OVER (PARTITION BY user_id ORDER BY Score DESC) R
FROM Src
) T
ORDER BY R, Score DESC, user_id
It yields:
User_Id Task_Name Score
____________________________________
1 101 10
2 104 10
6 112 10
3 106 9
4 107 9
If you need top 5 ordered, wrap results with another SELECT..ORDER clauses:
SELECT * FROM
(
SELECT TOP 5 user_id, Task_name, Score
FROM
(
SELECT *, RANK() OVER (PARTITION BY user_id ORDER BY Score DESC) R
FROM Src
) T
ORDER BY R, Score DESC, user_id
) E
ORDER BY Score DESC, user_id

Answer 2

I think this is what you want:
select top 5 t.*
from (select t.*,
row_number() over (partition by user_id order by score desc) as seqnum
from t
) t
where seqnum = 1
order by score desc;
The row_number() is used to select the best row for each user. The outer query then chooses the top 5 users with the tasks.