各外部キーの最小日付でレコードのレコード ID を取得するにはどうすればよいですか?

それを行う方法の 1 つは、

select A.ForeignKeyID, R.recordID
from (select distinct t.ForeignKeyID from table as t) as A
    outer apply
    (
        select top 1 t.recordID
        from table as t where t.ForeignKeyID = A.ForeignKeyID
        order by t.createdDate asc
    ) as R

SQL FIDDLE の例

それを行う別の方法は

select top 1 with ties
    t.recordID, t.ForeignKeyID
from table as t
order by row_number() over (partition by t.ForeignKeyID order by t.createdDate)

SQL FIDDLE の例

そして別の方法

select A.recordID, A.ForeignKeyID
from
(
    select
        t.recordID, t.ForeignKeyID,
        row_number() over (partition by t.ForeignKeyID order by t.createdDate) as RowNum
    from table1 as t
) as A
where A.RowNum = 1

SQL FIDDLE の例

コードが短いので、2 番目の方が好きです