mysql查询表中重复记录

1. 查找表中的重复记录（多字段）

select * from data as a where (a.user_id,a.start_at,a.end_at) in (select user_id,start_at,end_at from data group by user_id,start_at,end_at having count(*) > 1)；

参考文章：https://blog.csdn.net/qq_35834998/article/details/84847243