MySQL按时间戳分组

这取决于您的实际需求。如果您希望将属于同一分钟的记录分组在一起，而不管与先前记录的区别，那么简单的聚合就足够了：

select 
    date_format(created_at, '%Y-%m-%d %H:%i:00') date_minute,
    min(id) min_id, 
    max(id) max_id, 
    min(created_at) min_created_at, 
    max(created_at) max_created_at,
    count(*) no_records
from mytable
group by date_minute

另一方面，如果要建立间隔小于1分钟的连续记录组，则这是一个间隙和孤岛的问题。这是使用窗口函数（在MySQL 8.0中可用）解决它的方法：

select 
    min(id) min_id, 
    max(id) max_id, 
    min(created_at) min_created_at, 
    max(created_at) max_created_at,
    count(*) no_records
from (
    select
        t.*,
        sum(case when created_at < lag_created_at + interval 1 minute then 0 else 1 end) 
            over(order by created_at) grp
    from (
        select
            t.*,
            lag(created_at) over(order by created_at) lag_created_at
        from mytable t
    ) t
) t
group by grp