题解 | #删除记录（二）#
删除记录（二）
http://www.nowcoder.com/practice/964c9f7fffbb4ab18b507cfed4111b4a
delete from exam_record where id in( select id from ( select *,row_number()over(order by start_time) as rn from exam_record where submit_time is null&nbs***bsp;timestampdiff(minute,start_time,submit_time) < 5 ) t where rn <= 3 )
