SQL Server 2014

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CREATE TABLE A (
Store_ID nvarchar(20),   -- (ID)
Store_Name nvarchar(20), -- (店名)
Sales int,               -- (銷售額)
Txn_Dat nvarchar(20)     -- (日期) 
);

INSERT INTO A (Store_ID,Store_Name,Sales,Txn_Dat)
VALUES 
('1','x',10,'2021/10/01'),
('2','x',20,'2021/10/02'),
('3','y',50,'2021/10/03');

SELECT  *
FROM A


Store_ID
Store_Name
Sales
Txn_Dat


1
x
10
2021/10/01

2
x
20
2021/10/02

3
y
50
2021/10/03


CREATE TABLE B (
Region_Name nvarchar(20),   -- (區域)
Store_Name nvarchar(20)     -- (店名)
);

INSERT INTO B (Region_Name,Store_Name)
VALUES 
('M','x'),
('K','y'),
('G','Z');

SELECT *
FROM B


Region_Name
Store_Name


M
x

K
y

G
Z


SELECT B.Region_Name,P.Store_Name,ISNULL(P.Sales,0) AS Sales
FROM B
LEFT JOIN (
SELECT A.Store_Name,SUM(Sales) AS Sales
FROM A
GROUP BY A.Store_Name) AS P ON B.Store_Name=P.Store_Name 


Region_Name
Store_Name
Sales


M
x
30

K
y
50

G
null
0