1、统计每天首次登录的人数
sql
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-- 统计每天首次登录的人数
-- 步骤:先找出第一次登录的时间,再按首次登录时间分组求人数
-- 方法1:
select first_login_time, count(user_id) as cnt
from
(
select user_id, date_formate(min(login_ts), 'yyyy-MM-dd') as first_login_time
from user_login_detail
group by user_id
) t
group by first_login_time;
-- 方法2:
select date_format(t.login_ts, 'yyyy-MM-dd') as first_login_time, count(user_id) as cnt
from
(
select user_id, login_ts,
lag(login_ts) over(partition by user_id order by login_ts) as flag
from user_login_detail
where flag is NULL
) t
group by first_login_time;
2、查询用户注册日期(首次登录日期)、登录总次数、2021年登录总次数
sql
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-- 用户注册日期(首次登录日期)、登录总次数、2021年登录总次数
select user_id,
date_format(min(login_ts), 'yyyy-MM-dd') as first_login_time,
count(1) as login_cnt,
count(if(year(login_ts)=2021, 1, null)) as 2021_login_cnt
from user_login_detail
group by user_id;
3、查询每个用户累积访问次数
sql
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-- 3、每个用户累积访问次数
select user_id, visit_date, month_visit_cnt,
sum(month_visit_cnt) over(partion by user_id order by visit_date) as cum_month_visit_cnt
from
( -- 先求出用户每个月累计访问次数
select user_id, date_format(visit_date, 'yyyy-MM') as visit_date,
sum(visit_cnt) as month_visit_cnt
from tb_1
group by user_id, date_format(visit_date, 'yyyy-MM')
) t;
4、各直播间最大的同时在线人数
sql
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-- 各直播间最大的同时在线人数
select room_id, max(cnt) as max_cnt
from
(
select room_id, sum(flag) over(partion by room_id order by dt) as cnt
from
(
select room_id, user_id, login_time as dt,
1 as flag
from tb
union
select room_id, user_id, logout_time as dt,
-1 as flag
from tb
) t1
) t2
group by t2.room_id;
5、查询累计销量排名第二的商品
sql
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-- 查询累计销量排名第二的商品
select t2.sku_id
from
(
select t1.sku_id, t1.sum_cnt,
dense_rank() over(order by t1.sum_cnt desc) as rk
from
(
select sku_id, sum(sku_num) sum_cnt
from order_detail
group by sku_id
) t1
) t2
where t2.rk=2;
6、向用户推荐朋友收藏的商品
sql
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-- 向用户推荐朋友收藏的商品
-- 步骤:1、首先,单向好友变双向,得到(用户、朋友);再关联用户收藏表,得到(用户、朋友收藏商品);
-- 2、求出(用户、用户收藏集合)
-- 3、由(用户、朋友收藏商品)和(用户、用户收藏商品集合),找出朋友收藏的且不在用户收藏的商品
select t3.user_id, t3.sku_id
from
(
select distinct t1.user_id, t2.sku_id -- 同一个用户的多个朋友都收藏了同一个商品,所以要去重
from
(
select user1_id user_id,
user2_id friend_id
from friendship_info
union
select user2_id,
user1_id
from friendship_info
) t1
join favor_info t2
on t1.friend_id=t2.user_id
) t3
left join
(
select user_id,
collect_set(sku_id) sku_set
from favor_info
group by user_id
) t4
on t3.user_id=t4.user_id
where not array_contains(t4.sku_set, t3.sku_id);