--生成测试数据
declare @t table(id int,content varchar(5),buid int)
insert into @t select 1,'内容1',180
union all select 1,'内容2',180
union all select 1,'内容3',170
union all select 1,'内容4',180
union all select 1,'内容5',169
union all select 1,'内容6',169
--如果id有可能不同
select top 3 a.id,a.content,a.buid
from @t a
join(select content=min(content),buid from @t group by buid) b
on a.content=b.content
order by a.buid desc
--如果id都是一样
select top 3 id=min(id),content=min(content),buid
from @t
group by buid
order by buid desc