MSSQL: Only last entry in GROUP BY (with id) - sql

Question

Following / copying computhomas's question, but adding some twists...
I have the following table in MSSQL2008
id | business_key | result | date
1 | 1 | 0 | 9
2 | 1 | 1 | 8
3 | 2 | 1 | 7
4 | 3 | n | 6
5 | 4 | 1 | 5
6 | 4 | 0 | 4
And now i want to group based on the business_key returning the complete entry with the newest date.
So my expected result is:
id | business_key | result | date
1 | 1 | 0 | 9
3 | 2 | 1 | 7
4 | 3 | n | 6
5 | 4 | 1 | 5
I also bet that there is a way to achieve that, i just can't find / see / think of it at the moment.
edit: sorry about this, I actually meant something else from original question I did. I felt like editing this might be better than accepting a solution and making another question. my original problem was that I am not filtering by id.

Answer 1

SELECT t.*
FROM
(
SELECT *, ROW_NUMBER() OVER
(
PARTITION BY [business_key]
ORDER BY [date] DESC
) AS [RowNum]
FROM yourTable
) AS t
WHERE t.[RowNum] = 1

Answer 2

SELECT
*
FROM
mytable
WHERE
ID IN (SELECT MAX(ID) FROM mytable GROUP BY business_key)

Answer 3

SELECT
MAX(T1.id) AS [id],
T1.business_key,
T1.result
FROM
dbo.My_Table T1
LEFT OUTER JOIN dbo.My_Table T2 ON
T2.business_key = T1.business_key AND
T2.id > T1.id
WHERE
T2.id IS NULL
GROUP BY T1.business_key,
T1.result
ORDER BY MAX(T1.id)
Edited based on clarifications
SELECT M1.*
FROM My_Table M1
INNER JOIN
(
SELECT [business_key], MAX([date]) as MaxDate
FROM My_Table
GROUP BY [business_key]
) M2 ON M1.business_key = M2.business_key AND M1.[date] = M2.MaxDate
ORDER BY M1.[id]

Answer 4

Assuming the combination of business_key & date is unique then....
Working example (3rd time is a charm):
declare #src as table(id int, business_key int,result int,[date] int)
insert into #src
SELECT 1,1,0,9
UNION SELECT 2,1,1,8
UNION SELECT 3,2,1,7
UNION SELECT 4,3,1,6
UNION SELECT 5,4,1,5
UNION SELECT 6,4,0,4
;with bkdate(business_key,[date])
AS
(
select business_key,MAX([date])
from #src
group by business_key
)
select src.* from #src src
inner join bkdate
ON src.[date] = bkdate.date
and src.business_key = bkdate.business_key
order by id

Answer 5

How about (edited after question change):
with latestdate as (
select business_key, maxdate=max(date)
from the_table
group by business_key
), latest as (
select ID = max(id)
from the_table
inner join latestdate
on the_table.business_key=latestdate.business_key
and the_table.date=latestdate.maxdate
group by the_table.business_key
)
select the_table.*
from the_table
inner join latest
on latest.id=the_table.id