select 
distinct a.uid,
a.nick_name,
a.achievement
from 
user_info a
left join exam_record b
on a.uid=b.uid 
left join practice_record c
on a.uid=c.uid
where left(a.nick_name,2)='牛客'
and right(a.nick_name,1)='号'
and a.achievement>=1200 
and a.achievement<=2500
and (date_format(b.start_time,'%Y%m')='202109'
or date_format(c.submit_time,'%Y%m')='202109')