删除记录（一）

SQL115. 删除记录（一）

描述

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，即结束时间

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表中作答时间小于5分钟整且分数不及格（及格线为60分）的记录；

后台会执行您的SQL，然后通过 SELECT * FROM exam_record; 语句来筛选出剩下的数据，与正确数据进行对比。

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),
(1002, 9001, '2021-05-02 10:01:01', '2021-05-02 10:05:58', 60),
(1002, 9002, '2021-06-02 19:01:01', '2021-06-02 19:05:01', 54),
(1003, 9001, '2021-09-05 19:01:01', '2021-09-05 19:40:01', 49),
(1003, 9001, '2021-09-05 19:01:01', '2021-09-05 19:15:01', 70),
(1003, 9001, '2021-09-06 19:01:01', '2021-09-06 19:05:01', 80),
(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
3|1002|9001|2021-05-02 10:01:01|2021-05-02 10:05:58|60
5|1003|9001|2021-09-05 19:01:01|2021-09-05 19:40:01|49
6|1003|9001|2021-09-05 19:01:01|2021-09-05 19:15:01|70
7|1003|9001|2021-09-06 19:01:01|2021-09-06 19:05:01|80
8|1003|9002|2021-09-09 07:01:02|None|None

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: 35ms, 内存消耗: 6556KB, 提交时间: 2021-12-16

delete from exam_record
where timestampdiff(minute,start_time,submit_time) < 5 and score < 60

Mysql 解法, 执行用时: 36ms, 内存消耗: 6176KB, 提交时间: 2022-01-25

delete from exam_record where score<60 and DATE_SUB(submit_time,INTERVAL 5 MINUTE)<start_time;

Mysql 解法, 执行用时: 36ms, 内存消耗: 6180KB, 提交时间: 2022-01-25

DELETE FROM exam_record
WHERE TIMESTAMPDIFF(MINUTE, start_time, submit_time) < 5
    AND score < 60;

Mysql 解法, 执行用时: 36ms, 内存消耗: 6188KB, 提交时间: 2022-01-25

DELETE FROM exam_record
WHERE timestampdiff(MINUTE, start_time,submit_time) < 5 and score < 60;

Mysql 解法, 执行用时: 36ms, 内存消耗: 6192KB, 提交时间: 2022-01-26

delete from exam_record where 5>TIMESTAMPDIFF(MINUTE,start_time,submit_time) and score<60;

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