Question

I have a history table that contains a score per group per date (PK is group, date). What is the SQL query that can retrieve the scores for all groups for the 2nd most recent date?

ETA: The dates are the same across groups (each score is entered into the history table at the same time for each group).

Answer 1

select *
from ScoreHistory sc1
where exists
(
    select GroupId, max(ScoreDate) RecentScoreDate
    from ScoreHistory sc2
    where not exists
    (
        select GroupId, max(ScoreDate) RecentScoreDate
        from ScoreHistory sc3
        group by GroupId
        having GroupId = sc2.GroupId and max(ScoreDate) = sc2.ScoreDate
    )
    group by GroupId
    having GroupId = sc1.GroupId and max(ScoreDate) = sc1.ScoreDate
)

Setup:

create table ScoreHistory(GroupId int, ScoreDate datetime)

insert ScoreHistory
    select 1, '2011-06-14' union all
    select 1, '2011-06-15' union all
    select 1, '2011-06-16' union all
    select 2, '2011-06-15' union all
    select 2, '2011-06-16' union all
    select 2, '2011-06-17' 

The query would looks as simple as below for MS SQL 2005 +

;with cte
as
(
    select *, row_number() over(partition by GroupId order by ScoreDate desc) RowNumber
    from ScoreHistory
)
select *
from cte
where RowNumber = 2