咱们在实际项目中,有不少统计需求,最近就碰见一个须要,须要统计n天中的每一天的数据汇总,刚开始想的是统计前n天再减去n-1天的数据,可是这样写的话数据会很庞大,并且要走不少次sql sql
这样就比较耗性能了,经过查找本身组装了一个sql 性能
SELECT * FROM(SELECT ENTERPRISEID,SUM(CUSTOMERNUMBER)AS aaCUSTOMERNUMBER,SUM(SAVETEL)AS aaSAVETEL,SUM(FOLLOWNUMBER)AS aaFOLLOWNUMBER,SUM(FORWARDCARD)AS aaFORWARDCARD,SUM(SHOWCARD)AS aaSHOWCARD,SUM(RELIABLE) AS aaRELIABLE,(YEAR(CREATETIME)* 1000 + DAYOFYEAR(CREATETIME) DIV 1)AS groupNum FROM BEHAVIOR WHERE ENTERPRISEID = #{id} GROUP BY groupNum)AS aa ORDER BY groupNum DESC LIMIT #{cui}虽然有点长 可是更加实用。