1. 复习date_format(var,<date_type_str>)的使用方法。Y for yyyy;y for yy;M for 大学月份；m for mm
  2. 复习子查询和多列排序
SELECT r.job,r.mon,sum(r.num) as cnt FROM(
SELECT *,date_format(date,'%Y-%m') as mon FROM resume_info WHERE year(date)=2025
    ) r
group by r.job,r.mon
order BY r.mon desc,sum(r.num) desc