先不要聚合,改成下面的语句应该就了解了 select a1.name ,a1.sales,a2.name,a2.sales from Total_Sales a1,total_sales a2 where a1.sales < a2.sales or (a1.sales = a2.sales and a1.name <= a2.name) order by a1.sales desc ,a1.name desc; 两表通过连接条件进行关联,理解成先笛卡尔积再筛选,逻辑上好像也可以,不过有点别扭..
select a1.name ,a1.sales,a2.name,a2.sales
from Total_Sales a1,total_sales a2 where a1.sales < a2.sales or (a1.sales = a2.sales and a1.name <= a2.name)
order by a1.sales desc ,a1.name desc; 两表通过连接条件进行关联,理解成先笛卡尔积再筛选,逻辑上好像也可以,不过有点别扭..