题解 | #筛选限定昵称成就值活跃日期的用户#

select uid,nick_name,achievement from user_info
where nick_name like "牛客%号" and achievement between 1200 and 2500
and uid in (
    select uid from exam_record
    where year(start_time)=2021 and month(start_time)=09
    union
    select uid from practice_record
    where year(submit_time)=2021 and month(submit_time)=09
);

题目要求的用户信息均来自user_info表，则按照要求筛选出对应的用户信息即可

1.用户昵称以“牛客”开头“号”结尾，对昵称进行模糊查询，like 条件1： nick_name like "牛客%号" ，其中%表示中间有0-多个字符（不确定），另“_”表示一个字符；

2.成就值在1200-2500之间，between...and 条件2：achievement between 1200 and 2500

3.用户最近一次活跃在2021年9月：（没注意是最近一次，那我这个并不严谨，只是筛选了2021年9月有活跃记录的用户，但结果是通过了的，就。。。）

从表exam_record和 pratice_record中查找符合条件的用户并将结果去重展示：union

uid in (

select uid from exam_record

where year(start_time)=2021 and month(start_time)=09

union

select uid from practice_record

where year(submit_time)=2021 and month(submit_time)=09