oracle 求和并取出 日期最大的日期

select sum( t),da 　from (select '10' t, '2013-11-12' da
from dual
union
select '10' t, '2013-11-13' da
from dual
union
select '10' t, '2013-11-14' da
from dual
union
select '10' t, '2013-11-15' da
from dual
union
select '10' t, '2013-11-16' da
from dual
union
select '10' t, '2013-11-19' da
from dual
union
select '10' t, '2013-11-11' da from dual)

            group by da 


                            希望的到的结果是    70 ：：：： 2013-11-19
                            有没有函数啊！

把group by去掉，da改成用max(da)？