题解 | #筛选限定昵称成就值活跃日期的用户#

select uid,nick_name,achievement from(
select uid,nick_name,achievement,submit_time,'test'sign from user_info join exam_record using(uid)
union 
select uid,nick_name,achievement,submit_time,'pratice'sign from user_info join practice_record using(uid)
) t1
where nick_name regexp('^牛客.*号$') AND achievement between 1200 and 2500 AND year(submit_time) = 2021 and month(submit_time) = 9
group by uid,nick_name,achievement

可以把user_info 分别连接 exam_record，practice_record，之后用where 条件筛选即可