Help in query to get the max(date)

Question

Hi I have query like below and based on the query I get the following results,
SELECT a.UsageId,a.product,ProductDate
FROM dbo.table1 a
JOIN dbo.table2 b ON a.SID= b.SID
JOIN dbo.table3 c ON b.CID = c.CID
UsageId        Product          UsageDate
1 Yellow 2014-01-01
2 Yellow 2014-01-02
3 Yellow 2014-01-03
4 Yellow 2014-01-04
5 Red 2014-01-01
6 Red 2014-01-02
7 Blue 2014-01-03
8 Blue
2014-01-04
Now I want to add a new column which gives me the Max(UsageDate) of the column Prdouct last Usage.
UsageId        Product          UsageDate          Max(UsageDate)
1 Yellow
2014-01-01          2014-01-04
2 Yellow
2014-01-02    2014-01-04
3 Yellow
2014-01-03          2014-01-04
4 Yellow
2014-01-04          2014-01-04
5 Red 2014-01-01          2014-01-02 
6 Red 2014-01-02          2014-01-02
7 Blue
2014-01-03          2014-01-04
8 Blue
2014-01-04          2014-01-04

Answer 1

Simply use:
SELECT a.UsageId,a.product,ProductDate, MAX(ProductDate) OVER (PARTITION BY a.ProductID) as [Latest Product Usage Date]
FROM dbo.table1 a
JOIN dbo.table2 b ON a.SID= b.SID
JOIN dbo.table3 c ON b.CID = c.CID
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