题解 | #筛选限定昵称成就值活跃日期的用户#

#先筛选出uid，其应满足最近一次试卷或练习在2021年9月，在从第一个表找其他满足条件的字段
select uid,nick_name,achievement
from user_info
where uid in 
(
    select uid
    from exam_record
    group by uid
    having max(date_format(start_time,'%Y%m'))=202109
    union
    select uid
    from practice_record
    group by uid
    having max(date_format(submit_time,'%Y%m'))=202109
)
and nick_name like '牛客%号'
and achievement between 1200 and 2500