题解 | #筛选限定昵称成就值活跃日期的用户#

select distinct ui.uid, nick_name, achievement
from user_info ui left join (
    select uid, max(submit_time) act_time
    from exam_record
    group by uid
    union 
    select uid, max(submit_time) act_time
    from practice_record
    group by uid
) t1
on ui.uid = t1.uid
where nick_name like '牛客%号'
    and achievement between 1200 and 2500
    and date_format(act_time, '%Y%m') = '202109'