declare @t table ( ID int , name varchar(8),cj float)
insert into @t
select 1,'张三',90 union all
select 2,'张三',90 union all
select 3,'李四',80 union all
select 4,'李四',65 union all
select 5,'李四',20 union all
select 6,'张三',30 union all
select 7,'李四',90 union all
select 8,'李四',50 

select name,max(ID),replace(max(convert(char(8),id)+convert(varchar(8),cj)),
                            max(convert(char(8),id)),'')

from @t
group by name
---------------------------

(8 行受影响)
name                 
-------- ----------- ----------------------------------------------------------------------------------------------------------------
李四       8                  50
张三       6                  30

(2 行受影响)

------解决方案--------------------
SQL code

--楼主还可以这样 
declare @t table ( ID int , name varchar(8),cj float)
insert into @t
select 1,'张三',90 union all
select 2,'张三',90 union all
select 3,'李四',80 union all
select 4,'李四',65 union all
select 5,'李四',20 union all
select 6,'张三',30 union all
select 7,'李四',90 union all
select 8,'李四',50 

;with t as (

select row_number() over ( partition by name order by id desc) as Row ,* from @t 
)

select ID,name,cj from t where Row = 1


/×

(8 行受影响)
ID          name     cj
----------- -------- ----------------------
8           李四       50
6           张三       30

(2 行受影响)
×/

------解决方案--------------------
SQL code

--楼主还可以这样 

declare @t table ( ID int , name varchar(8),cj float)
insert into @t
select 1,'张三',90 union all
select 2,'张三',90 union all
select 3,'李四',80 union all
select 4,'李四',65 union all
select 5,'李四',20 union all
select 6,'张三',30 union all
select 7,'李四',90 union all
select 8,'李四',50 

select * from @t t where not exists(select 1 from @t where name=t.name and id>t.id)

/×

(8 行受影响)
ID          name     cj
----------- -------- ----------------------
6           张三       30
8           李四       50

(2 行受影响)

×/