MySQL-当没有记录时将结果设为零

create table model (
id int comment 'The model id. Primary Key',
name varchar(50) comment 'Models name',
price int comment 'The price of the model',
primary key (id)
);

create table country (
id int comment 'The country id. Primary Key',
name varchar(50) comment 'Countrys name',
primary key (id)
);

create table sales (
model_id int comment 'Models id',
country_id int comment 'Countrys id',
quantity int comment 'Number of units sold',
sales_date date comment 'Date of the sale'
);

INSERT INTO COUNTRY VALUES
(1, 'Brazil'),
(2, 'Italy'),
(3, 'China');

INSERT INTO model VALUES
(1, 'ZTX100', 100),
(2, 'AHT567', 200),
(3, 'JPF090', 300);

INSERT INTO sales VALUES
(1, '1', 500, '2017-01-10'),
(2, '2', 600, '2017-05-11'),
(3, '3', 700, '2017-07-21'),
(1, '3', 200, '2019-08-14');

我需要编写一个查询,计算所有车型的国别销售额以及2017年的收入。结果应采用以下格式:country|name| model|name| revenue

我正在尝试下面的查询。我需要把没有任何销售的国家/型号也带来,收入为0,但是我的查询只返回有任何销售的国家/型号。

SELECT c.name as country_name,
       m.name as model_name, 
       IFNULL(SUM(s.quantity * m.price),0) as revenue 
    FROM
    sales s
     right join model m on s.model_id = m.id
     right join country c on s.country_id = c.id
where date(s.sales_date) between '2017-01-01' and '2017-12-31'    
group by c.id, m.id
order by c.id, m.id;

查询结果

Brazil  ZTX100  50000
Italy   AHT567  120000
China   JPF090  210000

Brazil  ZTX100  50000
Brazil  AHT567  0
Brazil  JPF090  0

Italy   ZTX100  0
Italy   AHT567  120000
Italy   JPF090  0

China   ZTX100  0
China   AHT567  0
China   JPF090  210000

有一个简单的方法吗?

SELECT c.name as country_name, m.name as model_name, IFNULL(SUM(s.quantity * m.price),0) as revenue FROM country c cross join model m left join sales s on s.model_id = m.id and s.country_id = c.id and s.sales_date >= '2017-01-01' and s.sales_date < '2018-01-01' group by c.id, m.id, c.name, m.name order by c.id, m.id;