【牛客】SQL135 每个6/7级用户活跃情况

时间：2024-03-03 18:46:41

描述

现有用户信息表user_info（uid用户ID，nick_name昵称, achievement成就值, level等级, job职业方向, register_time注册时间）：

id uid nick_name achievement level job register_time
1 1001 牛客1号 3100 7 算法 2020-01-01 10:00:00
2 1002 牛客2号 2300 7 算法 2020-01-01 10:00:00
3 1003 牛客3号 2500 7 算法 2020-01-01 10:00:00
4 1004 牛客4号 1200 5 算法 2020-01-01 10:00:00
5 1005 牛客5号 1600 6 C++ 2020-01-01 10:00:00
6 1006 牛客6号 2600 7 C++ 2020-01-01 10:00:00

试卷信息表examination_info（exam_id试卷ID, tag试卷类别, difficulty试卷难度, duration考试时长, release_time发布时间）：

id exam_id tag difficulty duration release_time
1 9001 SQL hard 60 2021-09-01 06:00:00
2 9002 C++ easy 60 2021-09-01 06:00:00
3 9003 算法 medium 80 2021-09-01 10:00:00

试卷作答记录表exam_record（uid用户ID, exam_id试卷ID, start_time开始作答时间, submit_time交卷时间, score得分）：

uid exam_id start_time submit_time score
1001 9001 2021-09-01 09:01:01 2021-09-01 09:31:00 78
1001 9001 2021-09-01 09:01:01 2021-09-01 09:31:00 81
1005 9001 2021-09-01 19:01:01 2021-09-01 19:30:01 85
1005 9002 2021-09-01 12:01:01 2021-09-01 12:31:02 85
1006 9003 2021-09-07 10:01:01 2021-09-07 10:21:59 84
1006 9001 2021-09-07 10:01:01 2021-09-07 10:21:01 81
1002 9001 2020-09-01 13:01:01 2020-09-01 13:41:01 81
1005 9001 2021-09-01 14:01:01 (NULL) (NULL)

题目练习记录表practice_record（uid用户ID, question_id题目ID, submit_time提交时间, score得分）：

uid question_id submit_time score
1001 8001 2021-08-02 11:41:01 60
1004 8001 2021-08-02 19:38:01 70
1004 8002 2021-08-02 19:48:01 90
1001 8002 2021-08-02 19:38:01 70
1004 8002 2021-08-02 19:48:01 90
1006 8002 2021-08-04 19:58:01 94
1006 8003 2021-08-03 19:38:01 70
1006 8003 2021-08-02 19:48:01 90
1006 8003 2020-08-01 19:38:01 80

请统计每个6/7级用户总活跃月份数、2021年活跃天数、2021年试卷作答活跃天数、2021年答题活跃天数，按照总活跃月份数、2021年活跃天数降序排序。由示例数据结果输出如下：

uid act_month_total act_days_2021 act_days_2021_exam act_days_2021_question
1006 3 4 1 3
1001 2 2 1 1
1005 1 1 1 0
1002 1 0 0 0
1003 0 0 0 0

解释：6/7级用户共有5个，其中1006在202109、202108、202008共3个月活跃过，2021年活跃的日期有20210907、20210804、20210803、20210802共4天，2021年在试卷作答区20210907活跃1天，在题目练习区活跃了3天。

代码1：

with cte1 as(
    select uid
    from
    user_info
    where level=6 or level=7
),
cte2 as(
    select uid,start_time as act_time,'exam' as label from exam_record
    union
    select uid,submit_time as act_time,'question' as lebel from practice_record
),
cte3 as(
    select uid,
    count(distinct left(act_time,7)) as act_month_total
    from cte1 left join cte2 using(uid)
    group by uid
    order by act_month_total desc
),
cte4 as(
    select uid,
    count(distinct left(act_time,10)) as act_days_2021
    from cte1 left join cte2 using(uid)
    where left(act_time,4)=2021
    group by uid
),
cte5 as(
    select uid,
    count(distinct left(act_time,10)) as act_days_2021_exam
    from cte1 left join cte2 using(uid)
    where left(act_time,4)=2021 and label='exam'
    group by uid
),
cte6 as(
    select uid,
    count(distinct left(act_time,10)) as act_days_2021_question
    from cte1 left join cte2 using(uid)
    where left(act_time,4)=2021 and label='question'
    group by uid
)

select uid,
ifnull(act_month_total,0),ifnull(act_days_2021,0), 
ifnull(act_days_2021_exam,0),ifnull(act_days_2021_question,0)
from cte1 left join cte3 using(uid)
left join cte4 using(uid)
left join cte5 using(uid)
left join cte6 using(uid)
order by act_month_total desc,act_days_2021 desc

代码2（来源于讨论区的机智写法）：

SELECT uid,
COUNT(DISTINCT DATE_FORMAT(act_time,'%Y%m')) as act_month_total,
COUNT(DISTINCT IF(YEAR(act_time)=2021,act_time,null)) as act_days_2021,
COUNT(DISTINCT IF(YEAR(act_time)=2021 and tag='exam',act_time,null)) as act_days_2021_exam,
COUNT(DISTINCT IF(YEAR(act_time)=2021 and tag='question',act_time,null)) as act_days_2021_question
FROM user_info
LEFT JOIN  (
        SELECT uid,DATE(start_time) as act_time,'exam' as tag
        FROM exam_record
        UNION
        SELECT uid,DATE(submit_time) as act_time,'question' as tag
        FROM practice_record
)t
using(uid)
WHERE level>=6
GROUP BY uid
ORDER BY act_month_total DESC,act_days_2021 DESC;

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