现有一张试卷作答记录表exam_record,其中包含多年来的用户作答试卷记录,结构如下表: 作答记录表exam_record: start_time是试卷开始时间 submit_time 是交卷时间,即结束时间,如果未完成的话,则为空 Filed Type Null Key Extra Default Comment id int(11) NO PRI auto_increment (NULL) 自增ID uid int(11) NO (NULL) 用户ID exam_id int(11) NO (NULL) 试卷ID start_time datetime NO (NULL) 开始时间 submit_time datetime YES (NULL) 提交时间 score tinyint(4) YES (NULL) 得分 请删除exam_record表中未完成作答或作答时间小于5分钟整的记录中,开始作答时间最早的3条记录。 后台会通过 SELECT * FROM exam_record 语句来对比结果。
示例1

输入

drop table if EXISTS exam_record;
CREATE TABLE IF NOT EXISTS 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;
TRUNCATE exam_record;
INSERT INTO exam_record(uid, exam_id, start_time, submit_time, score) VALUES
(1001, 9001, '2020-01-01 22:11:12', '2020-01-01 23:16:12', 50),
(1001, 9002, '2020-01-02 09:01:01', '2020-01-02 09:06:00', 58),
(1001, 9002, '2020-01-02 09:01:01', '2020-01-02 09:05:01', 58),
(1002, 9001, '2021-05-02 10:01:01', '2021-05-02 10:06:58', 60),
(1002, 9002, '2021-06-02 19:01:01', null, null),
(1003, 9001, '2021-09-05 19:01:01', null, null),
(1003, 9001, '2021-09-05 19:01:01', null, null),
(1003, 9002, '2021-09-09 07:01:02', null, null);

输出

1|1001|9001|2020-01-01 22:11:12|2020-01-01 23:16:12|50
4|1002|9001|2021-05-02 10:01:01|2021-05-02 10:06:58|60
6|1003|9001|2021-09-05 19:01:01|None|None
7|1003|9001|2021-09-05 19:01:01|None|None
8|1003|9002|2021-09-09 07:01:02|None|None
加载中...