题解 | #更新记录（二）#
更新记录（二）
https://www.nowcoder.com/practice/0c2e81c6b62e4a0f848fa7693291defc
update exam_record set submit_time='2099-01-01 00:00:00' , score=0 where start_time<='2021-09-01 00:00:00' and submit_time is null
submit_time=null X
submit_time is null V
