响应式网站跟一般网站的区别,做网站 怎么做留言,东莞长安人才市场招聘信息,中能建设集团电子商务网站目录
1.可回收且低脂的产品
2.寻找用户推荐人 3.使用唯一标识码替换员工ID 4.产品销售分析 I
5.有趣的电影
6.平均售价
7.每位教师所教授的科目种类的数量
8.平均售价 1.可回收且低脂的产品 # Write your MySQL query statement below
select product_id
from Products
w…目录
1.可回收且低脂的产品
2.寻找用户推荐人 3.使用唯一标识码替换员工ID 4.产品销售分析 I
5.有趣的电影
6.平均售价
7.每位教师所教授的科目种类的数量
8.平均售价 1.可回收且低脂的产品 # Write your MySQL query statement below
select product_id
from Products
where low_fatsY and recyclableY
2.寻找用户推荐人 # Write your MySQL query statement below
select name
from Customer
where referee_id!2 使用不等于符号无法筛选null情况
# Write your MySQL query statement below
select name
from Customer
where id not in
(select id from Customer where referee_id2) 3.使用唯一标识码替换员工ID # Write your MySQL query statement below
#左连接
select e1.unique_id,e2.name
from Employees as e2
left join EmployeeUNI as e1
on e1.ide2.id4.产品销售分析 I # Write your MySQL query statement below
select p.product_name,s.year,s.price
from Sales as s
left join Product as p
on s.product_idp.product_id
5.有趣的电影 # Write your MySQL query statement below
select *
from cinema
where id%21 and description!boring
order by rating desc
6.平均售价 # Write your MySQL query statement below
#先完成正常的再完成为0的情况
select p.product_id,round(sum(p.price*u.units)/sum(u.units),2) as average_price
from Prices as p join UnitsSold as u
on p.product_idu.product_id
and u.purchase_date between p.start_date and p.end_date
group by product_id
#处理为0的情况
union all
select product_id,0 as average_price
from Prices
where product_id not in (select distinct product_id from UnitsSold) 7.每位教师所教授的科目种类的数量 # Write your MySQL query statement below
select teacher_id,count(distinct subject_id) as cnt
from teacher
group by teacher_id
8.平均售价 # Write your MySQL query statement below
select activity_date as day,count(distinct user_id) as active_users
from Activity
where datediff(2019-07-27,activity_date) between 0 and 29
group by activity_date
