未完成试卷数大于1的有效用户

id	uid	exam_id	start_time	submit_time	score
1	1001	9001	2021-07-02 09:01:01	2021-07-02 09:21:01	80
2	1002	9001	2021-09-05 19:01:01	2021-09-05 19:40:01	81
3	1002	9002	2021-09-02 12:01:01	(NULL)	(NULL)
4	1002	9003	2021-09-01 12:01:01	(NULL)	(NULL)
5	1002	9001	2021-07-02 19:01:01	2021-07-02 19:30:01	82
6	1002	9002	2021-07-05 18:01:01	2021-07-05 18:59:02	90
7	1003	9002	2021-07-06 12:01:01	(NULL)	(NULL)
8	1003	9003	2021-09-07 10:01:01	2021-09-07 10:31:01	86
9	1004	9003	2021-09-06 12:01:01	(NULL)	(NULL)
10	1002	9003	2021-09-01 12:01:01	2021-09-01 12:31:01	81
11	1005	9001	2021-09-01 12:01:01	2021-09-01 12:31:01	88
12	1005	9002	2021-09-01 12:01:01	2021-09-01 12:31:01	88
13	1006	9002	2021-09-02 12:11:01	2021-09-02 12:31:01	89

还有一张试卷信息表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），示例数据如下：

id	exam_id	tag	difficulty	duration	release_time
1	9001	SQL	hard	60	2020-01-01 10:00:00
2	9002	SQL	easy	60	2020-02-01 10:00:00
3	9003	算法	medium	80	2020-08-02 10:00:00

请统计2021年每个未完成试卷作答数大于1的有效用户的数据（有效用户指完成试卷作答数至少为1且未完成数小于5），输出用户ID、未完成试卷作答数、完成试卷作答数、作答过的试卷tag集合，按未完成试卷数量由多到少排序。示例数据的输出结果如下：

uid	incomplete_cnt	complete_cnt	detail
1002	2	4	2021-09-01:算法;2021-07-02:SQL;2021-09-02:SQL;2021-09-05:SQL;2021-07-05:SQL

解释：2021年的作答记录中，除了1004，其他用户均满足有效用户定义，但只有1002未完成试卷数大于1，因此只输出1002，detail中是1002作答过的试卷{日期:tag}集合，日期和tag间用:连接，多元素间用;连接。

示例1

输入:

drop table if exists examination_info;
CREATE TABLE examination_info (
    id int PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID',
    exam_id int UNIQUE NOT NULL COMMENT '试卷ID',
    tag varchar(32) COMMENT '类别标签',
    difficulty varchar(8) COMMENT '难度',
    duration int NOT NULL COMMENT '时长',
    release_time datetime COMMENT '发布时间'
)CHARACTER SET utf8 COLLATE utf8_general_ci;

drop table if exists exam_record;
CREATE TABLE  exam_record (
    id int PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID',
    uid int NOT NULL COMMENT '用户ID',
    exam_id int NOT NULL COMMENT '试卷ID',
    start_time datetime NOT NULL COMMENT '开始时间',
    submit_time datetime COMMENT '提交时间',
    score tinyint COMMENT '得分'
)CHARACTER SET utf8 COLLATE utf8_general_ci;

INSERT INTO examination_info(exam_id,tag,difficulty,duration,release_time) VALUES
  (9001, 'SQL', 'hard', 60, '2020-01-01 10:00:00'),
  (9002, 'SQL', 'easy', 60, '2020-02-01 10:00:00'),
  (9003, '算法', 'medium', 80, '2020-08-02 10:00:00');

INSERT INTO exam_record(uid,exam_id,start_time,submit_time,score) VALUES
(1001, 9001, '2021-07-02 09:01:01', '2021-07-02 09:21:01', 80),
(1002, 9001, '2021-09-05 19:01:01', '2021-09-05 19:40:01', 81),
(1002, 9002, '2021-09-02 12:01:01', null, null),
(1002, 9003, '2021-09-01 12:01:01', null, null),
(1002, 9001, '2021-07-02 19:01:01', '2021-07-02 19:30:01', 82),
(1002, 9002, '2021-07-05 18:01:01', '2021-07-05 18:59:02', 90),
(1003, 9002, '2021-07-06 12:01:01', null, null),
(1003, 9003, '2021-09-07 10:01:01', '2021-09-07 10:31:01', 86),
(1004, 9003, '2021-09-06 12:01:01', null, null),
(1002, 9003, '2021-09-01 12:01:01', '2021-09-01 12:31:01', 81),
(1005, 9001, '2021-09-01 12:01:01', '2021-09-01 12:31:01', 88),
(1005, 9002, '2021-09-01 12:01:01', '2021-09-01 12:31:01', 88),
(1006, 9002, '2021-09-02 12:11:01', '2021-09-02 12:31:01', 89);

输出:

1002|2|4|2021-07-02:SQL;2021-07-05:SQL;2021-09-01:算法;2021-09-02:SQL;2021-09-05:SQL

原站题解

上次编辑到这里，代码来自缓存点击恢复默认模板

Mysql 解法, 执行用时: 36ms, 内存消耗: 6408KB, 提交时间: 2022-01-25

SELECT uid, count(incomplete) as incomplete_cnt,
    count(complete) as complete_cnt,
    group_concat(distinct concat_ws(':', date(start_time), tag) SEPARATOR ';') as detail
from (
    SELECT uid, tag, start_time,
        if(submit_time is null, 1, null) as incomplete,
        if(submit_time is null, null, 1) as complete
    from exam_record 
    left join examination_info using(exam_id)
    where year(start_time)=2021
) as exam_complete_rec
group by uid
having complete_cnt >= 1 and incomplete_cnt BETWEEN 2 and 4
order by incomplete_cnt DESC

Mysql 解法, 执行用时: 37ms, 内存消耗: 6380KB, 提交时间: 2021-11-30

SELECT uid,
sum(if(submit_time is null, 1, 0)) as incomplete_cnt, 
sum(if(submit_time is null, 0, 1)) as complete_cnt,
#count(case when score is null then start_time else null end) as incomplete_cnt,
#count(case when score is not null then submit_time else null end) as complete_cnt,
group_concat(distinct CONCAT(DATE_FORMAT(start_time, '%Y-%m-%d'),':',tag) separator ';') as detail
#GROUP_CONCAT(DISTINCT CONCAT(date_format(submit_time,'%Y-%m-%d'),':',tag) separator ';') as detail
from exam_record er join examination_info ei ON er.exam_id=ei.exam_id
where YEAR(start_time)=2021
group by uid 
having incomplete_cnt>1
and incomplete_cnt<5
and complete_cnt >= 1
order by incomplete_cnt desc

Mysql 解法, 执行用时: 37ms, 内存消耗: 6384KB, 提交时间: 2021-12-18

WITH temp AS (
    SELECT
        uid,
        count(*) - count(submit_time) AS `incomplete_cnt`,
        count(submit_time) AS 'complete_cnt',
        group_concat(distinct concat_ws(':', date(start_time), tag) SEPARATOR ';') as detail
    FROM exam_record er
    JOIN examination_info ei
    ON er.exam_id = ei.exam_id
    WHERE YEAR(start_time) = 2021
    GROUP BY uid
    HAVING count(submit_time) >= 1 AND (count(*) - count(submit_time)) < 5
 )
SELECT
*
FROM temp
WHERE incomplete_cnt > 1
ORDER BY incomplete_cnt DESC;

# select uid
#         , sum(if(submit_time is null, 1, 0)) as incomplete_cnt
#         , sum(if(submit_time is null, 0, 1)) as complete_cnt
#         , group_concat(distinct CONCAT(DATE_FORMAT(start_time, '%Y-%m-%d'),':',tag) separator ';') as detail
# from exam_record er join examination_info ei on er.exam_id = ei.exam_id
# where YEAR(start_time) = 2021
# group by uid
# having incomplete_cnt>1
# and incomplete_cnt<5
# and complete_cnt >= 1
# order by incomplete_cnt desc

Mysql 解法, 执行用时: 37ms, 内存消耗: 6384KB, 提交时间: 2021-12-17

-- 2021年每个未完成试卷作答数大于1的有效用户的数据（有效用户指完成试卷作答数至少为1且未完成数小于5）
select
er.uid
,sum(case when er.submit_time is null then 1 else 0 end) incomplete_cnt 
,sum(case when er.submit_time is not null then 1 else 0 end) complete_cnt 
,group_concat(distinct concat(date_format(er.start_time,'%Y-%m-%d'),':',ei.tag) order by start_time separator ';') detail
from exam_record er left outer join examination_info ei
on er.exam_id=ei.exam_id
where year(er.start_time)='2021'
group by er.uid
having complete_cnt>=1 and incomplete_cnt between 2 and 4
order by incomplete_cnt desc;

Mysql 解法, 执行用时: 37ms, 内存消耗: 6384KB, 提交时间: 2021-12-02

select uid,(count(*)-count(submit_time)) as incompelete_cnt,count(submit_time) as compelete_cnt,
group_concat(distinct concat(date(start_time),':',tag) separator ';') as detail
from exam_record as er
join examination_info as ei on er.exam_id=ei.exam_id
where year(start_time)=2021
group by uid
having compelete_cnt>=1 and incompelete_cnt BETWEEN 2 and 4
order by incompelete_cnt desc

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