oracle查询分组数据中的最后一条数据和每组的数量

实现代码：

select tmp.* from(
    select ROW_NUMBER() OVER(partition by u.id order by u.name) rn,
    u.id,
    u.name,
    u.password pwd
    from tb_user u
    group by
    u.id,
    u.name,
    u.password
)tmp
where rn = 1