为没有任何对应值的组生成记录

Question

请考虑这个脚本：

declare @Table_City     table(CityName   varchar(50));
declare @Table_Product      table(ProductName   varchar(50));
declare @Table_Data     table(CityName   varchar(50), ProductName  varchar(50), [Count]    int, Price    int)

insert into @Table_City values('Paris'),('London'),('Tokyo'),('Roma'),('Bern'),('Aten')
insert into @Table_Product values('Toys'),('Shoe'),('TV'),('Radio')
insert into @Table_Data values
    ('Paris', 'Shoe', 12, 10000),
    ('Paris', 'TV', 6, 1040),
    ('Bern', 'Radio', 1, 10),
    ('London', 'TV', 32, 21132),
    ('Roma', 'Shoe', 120, 654400),
    ('Aten', 'TV', 20, 35000),
    ('Paris', 'Radio', 17, 2000),
    ('Paris', 'Radio', 2, 300),
    ('Tokyo', 'TV', 100, 1002000),
    ('Aten', 'TV',20 ,4000 ),
    ('Bern', 'TV', 35, 5000),
    ('London', 'Radio', 70, 7000),
    ('London', 'TV',10 ,10000 ),
    ('Aten', 'Shoe',200 ,10500 ),
    ('London', 'Toys', 10, 8000),
    ('Paris', 'Toys',80 , 9000),
    ('Paris', 'Radio',50 ,75000 ),
    ('Tokyo', 'Shoe',45 ,5500 ),
    ('Roma', 'Toys',12 ,6000 ),
    ('Bern', 'Toys',50 ,4800 ),
    ('London', 'TV',40 ,8700 ),
    ('Aten', 'Toys', 80 ,2500 ),
    ('Aten', 'TV', 100 ,12500 )

select CityName, ProductName , sum([count]) , sum(price)
from @Table_Data
group by CityName, ProductName
order by 1, 2

这个脚本生成这个结果：

但我想要这个结果：

为那些在组中没有对应值的记录生成 0 条记录的最佳方法是什么？

Answer 1

使用isnull()、cross apply，然后再加入我们的tabledata

SELECT t1.CityName, t2.ProductName, 
       SUM(isnull(d.[Count], 0)) as [Count],
       SUM(isnull(d.[Price], 0)) as [Price]
FROM   @Table_City t1
       CROSS JOIN @Table_Product t2
       LEFT JOIN @Table_Data d ON t1.CityName = d.CityName
             AND d.ProductName = t2.ProductName
GROUP BY t1.CityName, t2.ProductName
ORDER BY t1.CityName, t2.ProductName

Answer 2

你 CROSS JOIN @Table_City 和 @Table_Product 然后你 LEFT JOIN 到 @Table_Data

SELECT c.CityName, p.ProductName, 
       SUM(COALESCE([Count], 0)) as [Count],
       SUM(COALESCE([Price], 0)) as [Price]
FROM   @Table_City c
       CROSS JOIN @Table_Product p
       LEFT  JOIN @Table_Data d     ON c.CityName    = d.CityName
                                   AND p.ProductName = d.ProductName
GROUP BY c.CityName, p.ProductName