How Do I create a view that shows the total number of items a customer buys from the business in April 2019 along with the total price in SQL?

Question

I'm struggling to create a view in SQL that will the total number of items a customer buys from the business in April 2019 along with the total price. Here are my tables.

CREATE TABLE Customer ( 
CustID int AUTO_INCREMENT,
Fname varchar(50) NOT NULL,
Sname varchar(50) NOT NULL,
PRIMARY KEY (CustID)
);

 CREATE TABLE Transaction ( 
 TransID int AUTO_INCREMENT,
 OrderDate date NOT NULL,
 ArriveDate date NOT NULL,
 CustID int,
 PRIMARY KEY (TransID),
 FOREIGN KEY (CustID) REFERENCES Customer(CustID)
);

CREATE TABLE TransactionDetails(
TranDetID int AUTO_INCREMENT NOT NULL,
quantity int NOT NULL,
price int NOT NULL,
TransID int,
PRIMARY KEY (TranDetID),
FOREIGN KEY (TransID) REFERENCES Transaction(TransID)
);

Answer 1

Hope this helps. you can change the year and month using the 1st 2 lines of code

DECLARE @Year INT = 2019,
        @Month NVARCHAR(15) = 'April'

SELECT C.Fname, SUM(TD.quantity) AS quantity, SUM(TD.price) AS price
FROM [Transaction] T
LEFT JOIN customer C ON C.CustID = T.CustID
LEFT JOIN TransactionDetails TD ON TD.TransID = T.TransID
WHERE DATENAME(month, OrderDate) = @Month AND DATENAME(YEAR, OrderDate) = @Year
GROUP BY C.Fname

Answer 2

Seems curious, but:

select td.custid, sum(quantity) as total_quantity,
       sum(price) as total_price. -- perhaps "price * quantity"???
from transactions t join
     transactiondetails td
     using (TransID)
where t.orderdate >= '2019-04-01' and t.orderdate < '2019-05-01';

This is curious because your data model does not distinguish between products, which I would expect. It is unclear whether the price needs to be multiplied by the quantity, because you have no sample data and desired results.