SQL备忘

1、

table:test

id     fname    seq

1      1           1
2      1           2
3      1           3
4      2           1
5      2           2

sql:

select *
          from test A
         where id = (select id
                       from (select * from test order by seq desc)
                      where (A.Fname = fname and rownum <= 1))

---------------------------------------------------------------------------------
select * from
(select rank() over (partition by b.name order by b.seq desc)rk,b.* 
from test b) t
where t.rk<=1;