楼主，第二题你说的那个时间间隔我不是很明白呀……有空时能帮我解释一下吗？

我是这样写的：

select nums,avg(age) as avg_age
from
(select user_id,count(distinct pv_id) as nums
from pv_log
group by user_id) a left join dim_user b
on a.user_id=b.user_id
group by nums