现有试卷信息表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++ hard 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）： id uid exam_id start_time submit_time score 1 1001 9001 2021-09-01 09:01:01 2021-09-01 09:51:01 78 2 1001 9002 2021-09-01 09:01:01 2021-09-01 09:31:00 81 3 1002 9002 2021-09-01 12:01:01 2021-09-01 12:31:01 81 4 1003 9001 2021-09-01 19:01:01 2021-09-01 19:59:01 86 5 1003 9002 2021-09-01 12:01:01 2021-09-01 12:31:51 89 6 1004 9002 2021-09-01 19:01:01 2021-09-01 19:30:01 85 7 1005 9001 2021-09-01 12:01:01 2021-09-01 12:31:02 85 8 1006 9001 2021-09-07 10:01:01 2021-09-07 10:21:01 84 9 1003 9001 2021-09-08 12:01:01 2021-09-08 12:11:01 40 10 1003 9002 2021-09-01 14:01:01 (NULL) (NULL) 11 1005 9001 2021-09-01 14:01:01 (NULL) (NULL) 12 1003 9003 2021-09-08 15:01:01 (NULL) (NULL) 找到第二快和第二慢用时之差大于试卷时长的一半的试卷信息，按试卷ID降序排序。由示例数据结果输出如下： exam_id duration release_time 9001 60 2021-09-01 06:00:00 解释：试卷9001被作答用时有50分钟、50分钟、30分1秒、11分钟、10分钟，第二快和第二慢用时之差为50分钟-11分钟=39分钟，试卷时长为60分钟，因此满足大于试卷时长一半的条件，输出试卷ID、时长、发布时间。
示例1

输入

drop table if exists examination_info,exam_record;
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;

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, '2021-09-01 06:00:00'),
  (9002, 'C++', 'hard', 60, '2021-09-01 06:00:00'),
  (9003, '算法', 'medium', 80, '2021-09-01 10:00:00');

INSERT INTO exam_record(uid,exam_id,start_time,submit_time,score) VALUES
(1001, 9001, '2021-09-01 09:01:01', '2021-09-01 09:51:01', 78),
(1001, 9002, '2021-09-01 09:01:01', '2021-09-01 09:31:00', 81),
(1002, 9002, '2021-09-01 12:01:01', '2021-09-01 12:31:01', 81),
(1003, 9001, '2021-09-01 19:01:01', '2021-09-01 19:59:01', 86),
(1003, 9002, '2021-09-01 12:01:01', '2021-09-01 12:31:51', 89),
(1004, 9002, '2021-09-01 19:01:01', '2021-09-01 19:30:01', 85),
(1005, 9001, '2021-09-01 12:01:01', '2021-09-01 12:31:02', 85),
(1006, 9001, '2021-09-07 10:01:01', '2021-09-07 10:12:01', 84),
(1003, 9001, '2021-09-08 12:01:01', '2021-09-08 12:11:01', 40),
(1003, 9002, '2021-09-01 14:01:01', null, null),
(1005, 9001, '2021-09-01 14:01:01', null, null),
(1003, 9003, '2021-09-08 15:01:01', null, null);

输出

9001|60|2021-09-01 06:00:00
加载中...