MariaDB 10.5

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CREATE TABLE revenue(
Customer varchar(10),
Price	int,
Quantity int,
OrderDate date);
insert into revenue values
('xxx',	12,5,'2021-03-25'),
('yyy',	15,7,'2021-05-15'),
('xxx',	34,2,'2022-08-21');
with cust as 
(select distinct customer c from revenue),
years as
(select distinct year(OrderDate) y from revenue)
select 
y "year",
c customer ,
sum(price*quantity) revenue
from years 
cross join cust 
left join revenue r
on cust.c = r.customer and years.y = year(OrderDate)
group by 
c,y,
year(OrderDate)
order by y,c


year
customer
revenue


2021
xxx
60

2021
yyy
105

2022
xxx
68

2022
yyy
null