Order에서 총합을 구하는 함수

select sum(p.Price) Total
from customer.orders o
inner join Products p on o.ProductId=p.id
inner join Customer c on o.CustomerID=c.id;

이름별로 총합 구하기

select c.LastName, sum(p.Price) Total
from customer.orders o
inner join Products p on o.ProductId=p.id
inner join Customer c on o.CustomerID=c.id
group by c.LastName;

select c.LastName, p.ProductName, sum(p.Price) Total
from customer.orders o
inner join Products p on o.ProductId=p.id
inner join Customer c on o.CustomerID=c.id
group by c.LastName, p.ProductName;

시티별로 합과 평균을 구하기

select c.City, sum(p.Price) Total, avg(p.price)
from customer.orders o
inner join Products p on o.ProductId=p.id
inner join Customer c on o.CustomerID=c.id
group by c.City;

링크를 클릭하세요

https://youtu.be/9Pzj7Aj25lw?list=PLD20298E653A970F8&t=3413