with temp1(login_id,name,post_name) as(
select 1,'张三','java' from dual
union all select 2,'李四','.net' from dual
),
temp2(login_id,name,pro_post_name,result,"desc",time) as(
select '1','张三','java',1,'desc1',to_date('2012-05-12','yyyy-mm-dd') from dual
union all select '1','张三','java',2,'desc2',to_date('2012-06-05','yyyy-mm-dd') from dual
union all select '2','李四','java',2,'desc3',to_date('2012-05-22','yyyy-mm-dd') from dual
union all select '2','李四','.net',2,'desc4',to_date('2012-05-12','yyyy-mm-dd') from dual
)
select a.login_id,a.name,a.post_name,b.result,b."desc"
from temp1 a
inner join temp2 b on a.login_id=b.login_id and a.post_name=b.pro_post_name
    and b.time=(select max(time) from temp2 c where c.login_id=b.login_id and c.pro_post_name=b.pro_post_name);
/*
  LOGIN_ID NAME         POST_NAM     RESULT desc                                
---------- ------------ -------- ---------- ----------                          
         1 张三         java              2 desc2                               
         2 李四         .net              2 desc4   
*/