一条SQL语句如何求环比！这个月简历数减去上个月的（如图）
【这个月简历数】-【上个月的简历数】=【环比数】（如图）
sql语句如何写？
SELECTDATE_FORMAT(m_adddate,'%m') as month,count(m_id) as zong,DATE_FORMAT(m_adddate,'%Y') as year from job_myreceive where DATE_FORMAT(m_adddate,'%Y')=2011 GROUP BY DATE_FORMAT(m_adddate,'%m');
[解决办法]
嗯，这样写清楚些
SELECT DATE_FORMAT(a.m_adddate,'%Y%m') as Ym, count(*) as `当月`,
(select count(*) from job_myreceive where
DATE_FORMAT(a.m_adddate,'%Y%m') = DATE_FORMAT(DATE_add(m_adddate,INTERVAL 1 MONTH),'%Y%m')
) as 上月
FROM job_myreceive a group by 1
Ym 当月 上月
201012 6 0
201101 2 6
201105 1 0
201107 2 0
201112 1 0
201305 1 0
