题解 | #删除记录（二）#
删除记录（二）
https://www.nowcoder.com/practice/964c9f7fffbb4ab18b507cfed4111b4a
DELETE FROM exam_record
WHERE DATE_SUB(submit_time, INTERVAL 5 MINUTE) < start_time
OR submit_time IS NULL
LIMIT 3
/* 等价写法
WHERE TIMESTAMPDIFF(start_time,submit_time,MINUTE) < 5
OR submit_time IS NULL
WHERE DATE_SUB(submit_time, INTERVAL 5 MINUTE) < start_time
OR submit_time IS NULL
*/
