select * from ss  where portid in (select max(portid) from ss group by services)

------解决方案--------------------
select table1.* from table1,(select max(portid) as portid,services from table1 group by services) t2 where table1.portid=t2.portid and table1.services=t2.services;

------解决方案--------------------
portid  cococd  services  
9 1 b2  
4 1 m2  
5 9 m2  

select a.* from tb a,
(select services,max(portid) portid from tb group by services) b
where a.services = b.services and a.portid = b.portid

------解决方案--------------------
select * from tablename T where portid in(
select top 1 portid from tablename where services=T.services order by protid desc)

------解决方案--------------------

select * from #temp t where not exists
(select 1 from #temp where portid>t.portid and services=t.services)

------解决方案--------------------
select services from t1 where cocode in (select code from t2)

------解决方案--------------------
create table t11(services varchar(10),cocode int)
insert into t11 select 'b2',1
insert into t11 select 'm2',9

create table t12(code int)
insert into t12 select 6
insert into t12 select 9

select t11.services from t11,t12 where t11.cocode=t12.code

------解决方案--------------------
select services from t1 where cococd in(select code from t2)

------解决方案--------------------
8楼的嵌套与9楼的联接~

------解决方案--------------------
同意9楼的