一个面试题

create table tb_product

(

prod_id int , --商品编号

category_id int, ----商品类别

prod_name varchar(100) ----商品名称

)

create table tb_sales

(

prod_id int , ---商品编号

num int, ----销售数量

price float -----销售单价

)

tb_product 表数据 商品表数据

1 1
1 背心

2 2 1裤衩

3 3 2面包

4 4 2牛奶

5 5 1衬衣

6 6 1内裤

tb_sales 表数据 销售表数据

1 1
1 1.2

2 1 21.3

3 2 15

4 2 36

5 3 11

6 3 11.5

7 4 11

8 4 11

9 6 11

1、查询销售数量排行前十位的商品编号、名称、及总数量、总价格

select * from

(

select a.prod_name,a.prod_id,case when b.shuliang is NULL then 0 else shuliang end shuliang , case when b.zongjia is NULL then 0 else zongjia end zongjia from tb_product a left join

(select prod_id,sum(num) shuliang, sum(num*price) zongjia from tb_sales group by prod_id) b on a.prod_id=b.prod_id order by shuliang desc

)

where rownum<10

2、查询每类商品中销售数量排行前三的商品编号、商品名称、 商品类别

select * from (

select a.category_id,a.prod_name,a.prod_id,case when b.shuliang is NULL then 0 else shuliang end shuliang , case when b.zongjia is NULL then 0 else zongjia end zongjia from tb_product a left join

(select prod_id, sum(num) shuliang, sum(num*price) zongjia from tb_sales group by prod_id) b on a.prod_id=b.prod_id order by shuliang desc ) s1 where s1. shuliang

in (

select shuliang from

(

select a.category_id,a.prod_name,a.prod_id,case when b.shuliang is NULL then 0 else shuliang end shuliang , case when b.zongjia is NULL then 0 else zongjia end zongjia from tb_product a left join

(select prod_id, sum(num) shuliang, sum(num*price) zongjia from tb_sales group by prod_id) b on a.prod_id=b.prod_id order by shuliang desc

) s2 where s1.category_id=s2.category_id and rownum <=3

) order by s1.category_id,s1.shuliang desc