select vip,
count(visit_time) visit_nums,
count(distinct user_id) visit_users
from visit_tb join uservip_tb using(user_id)
group by vip
order by visit_nums desc

distinct 如果要放在函数外面，则必须放在所有字段之前

但如果要单独对某一列去重，必须放在函数里面