if object_id('tempdb..#t1') is not null
 drop table #t1 

create table #t1 (SKU# char(5), [Description] varchar(200), SalesDate datetime)

Insert into #t1 ([SKU#],  [Description],  SalesDate) Values('01110', 'Red Car with stripe', '01/19/2009')
Insert into #t1 ([SKU#],  [Description],  SalesDate) Values('01110', 'Red Car with line',   '02/01/2009')
Insert into #t1 ([SKU#],  [Description],  SalesDate) Values('01110', 'Red Car with laser',  '02/25/2009')
Insert into #t1 ([SKU#],  [Description],  SalesDate) Values('01120', 'Blue Car with stripe', '01/19/2009')
Insert into #t1 ([SKU#],  [Description],  SalesDate) Values('01120', 'Blue Car with line',   '02/05/2009')
Insert into #t1 ([SKU#],  [Description],  SalesDate) Values('01120', 'Blue Car with laser',  '02/20/2009')

;with cte
AS
(SELECT *, row_number() over(partition by [sku#] order by SalesDate desc) rn
from #t1
)
select [SKU#],  [Description],  SalesDate
from cte
where rn =1

create table # (SKU# varchar(10), Description  varchar(128), SalesDate  datetime)

insert #
select '01110', 'Red Car with stripe', '01/19/2009'
union all select '01110', 'Red Car with line', '02/01/2009'
union all select '01110', 'Red Car with laser', '02/25/2009'
union all select '01120', 'Blue Car with stripe', '01/19/2009'
union all select '01120', 'Blue Car with line', '02/01/2009'
union all select '01120', 'Blue Car with laser', '02/25/2009'

select [sku#], [description], [SalesDate] from 
(select *, row_number() over (partition by SKU# order by salesDate desc) as rownum  from #) x
where rownum=1

---  Have a look at new and old data side by side
select a.[sku#], a.[description], a.[SalesDate], x.[description] as new from 
(select *, row_number() over (partition by SKU# order by salesDate desc) as rownum  from #) x
inner join # a on a.sku# = x.sku#
where rownum=1


--  Run the update
UPDATE a set  a.[description] = x.[description] 
from 
(select *, row_number() over (partition by SKU# order by salesDate desc) as rownum  from #) x
inner join # a on a.sku# = x.sku#
where rownum=1


--  Have a look at new values
select * from #