题解 | #商品交易(网易校招笔试真题)#
商品交易(网易校招笔试真题)
http://www.nowcoder.com/practice/f257dfc1b55e42e19eec004aa3cb4174
本题思路较为简单，sum()函数 + join连接
select g.id,g.name,g.weight,t.s from goods g join # 将goods表同表t按商品id连接
(select goods_id gi,sum(count) s
from trans group by gi) t # 将商品id以及该商品的购买总数量建为表t
on g.id = t.gi
where g.weight < 50 # 筛选重量超过50g的商品
and t.s > 20 # 筛选购买总数超过20次的商品
order by g.id # 按商品id升序排列
