declare @id int
--建一个临时表
if object_id('Tempdb..#temp') is not null
begin
    drop table #temp
end 
else 
begin
    create table #temp
    (
        [用户ID] int ,
        [更新日期] varchar(100),
        [更新动作] varchar(200)
    )
end

declare cursor1 cursor for --用游标
select distinct UserId from [你的表]
open cursor1
fetch next from cursor1 into @id

while @@fetch_status=0
begin
    insert into #temp
    select top 1 UserId,UpdateDate,Action from [你的表] where UserId = @id
        order by UpdateDate desc
    fetch next from cursor1 into @id
end
close cursor1
deallocate cursor1

select * from  #temp
drop table #temp