select max(price),min(price),cate_name from goods group by cate_name;
求每类产品的最大最小值
子查询—大于平均价格的商品价格
select * from goods where price >(select avg(price) from goods);
查询每种类型中最贵的电脑信息
select cate_name,max(price) from goods group by cate_name;
select * from goods inner join (select max(price) as max_price,min(price) as min_price,cate_name,avg(price) as avg_price from goods group by cate_name) as goods_new_info on goods.cate_name = goods_new_info.cate_name and goods.price=goods_new_info.max_price;