题解 | #实习广场投递简历分析(二)#

第一步先将日期用 DATE_FORMAT按月份'%Y-%m'分组，并将job,num字段用where用2025年内筛选出来，整体备用，即
(SELECT job,
    DATE_FORMAT(date, '%Y-%m') AS mon,
    num
    from resume_info
    where 
    date between '2025-01-01' and '2026-01-01') as a
第二步，对cnt求和，并通过job、mon进行分组，然后易错点使用 ORDER BY 子句对多个列进行排序时，如果第一列的值相等，MySQL 将根据第二列的值进行默认升序排序，所以需使用 DESC 关键字来指定降序排序，即
   select a.job,a.mon,
sum(a.num) as cnt
from
(SELECT job,
    DATE_FORMAT(date, '%Y-%m') AS mon,
    num
    from resume_info
    where 
    date between '2025-01-01' and '2026-01-01') as a
group by a.mon,a.job
order by a.mon desc,cnt desc