题解 | #插入记录（一）#

insert into exam_record(uid, exam_id, start_time, submit_time, score) values
(1001, 9001, '2021-09-01 22:11:12', '2021-09-01 22:11:12' + interval 50 minute, 90), 
(1002, 9002, '2021-09-04 07:01:02', null, null)
#一、插入记录的方式汇总：
#普通插入（全字段）：INSERT INTO table_name VALUES (value1, value2, ...)
#普通插入（限定字段）：INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...)
#多条一次性插入：INSERT INTO table_name (column1, column2, ...) VALUES (value1_1, value1_2, ...), (value2_1, value2_2, ...), ...
#从另一个表导入：INSERT INTO table_name SELECT * FROM table_name2 [WHERE key=value]

#二、interval用法
# 1. 使用`DATE_ADD`函数：
# 1.1 基本用法：SELECT DATE_ADD(NOW(), INTERVAL 1 DAY) AS tomorrow;
# 1.2 指定时间单位：SELECT DATE_ADD(NOW(), INTERVAL 2 HOUR) AS two_hours_later;
# 2. 使用`DATE_SUB`函数：
# 2.1 基本用法：SELECT DATE_SUB(NOW(), INTERVAL 1 WEEK) AS one_week_ago;
# 2.2 指定时间单位：SELECT DATE_SUB(NOW(), INTERVAL 3 MONTH) AS three_months_ago;
# 3. 直接使用`INTERVAL`：SELECT NOW() + INTERVAL 5 DAY AS five_days_later;
# 4. 示例：计算两个日期之间的差距：SELECT DATEDIFF('2024-02-05', '2024-01-01') AS date_difference;
# 5. 示例：计算时间差：SELECT TIMEDIFF('14:30:00', '12:45:00') AS time_difference;