Mysql中笔试问题解决

一、问题提出 1、表结构rru如下     2、要求查询显示结果为    二、问题解决 　　　方式一： 　　　　　SELECT DISTINCT c.`year` AS YEAR, (SELECT amcount FROM product WHERE YEAR= c.`YEAR`  AND  MONTH = "1"  )AS m1, (SELECT amcount FROM product WHE

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