Question

I have two tables that I need to create a query for. I’m sure I’ll need to join them as well.

I need to take the CustomerName and Address of customer from my Customer table but I also need the query to show the total dollar amount of all the orders placed by customer. So if the customer spent for example $300 dollars this year in total, that $300 is the output I’m trying to achieve.

I have a table called Order Details that uses an OrderID which is tied to a CustomerID and there are unitprice and quantity columns in the Order Details table. I’m trying to figure out how to multiple these but I am going crazy.

I have tried this to get at least the total from the orders but I have syntax errors for sure:

SELECT unitprice, 
       quantity 
FROM   [Order details] (unitprice * quantity) AS Totalorders, 
       from [Order Details] 
WHERE  orderid > 0 

also this without any luck :

SELECT customers.companyname                                AS 'Company Name', 
       customers.address                                    AS 'Address', 
       [order details].unitprice * [order details].quantity AS 'Orders' 
FROM   customers 
       LEFT JOIN orders 
              ON customers.customerid = orders.customerid 
ORDER  BY customers.companyname, 
          customers.address, 
          orders 

Thanks

Answer 1

You need to join in the order details and do a group by aggregation:

SELECT c.CompanyName AS "Company Name",
       c.Address AS "Address",
       sum(od.Unitprice * od.quantity) as "Orders"
FROM Customers c LEFT JOIN
     Orders o
     ON c.CustomerID = o.CustomerID left join
     [Order Details] od
     on od.orderid = o.orderid
GROUP BY c.CompanyName, c.Address
ORDER BY c.CompanyName, c.Address

In addition, I made some stylistic changes. I added aliases to the table names. I find it much easier to read c.CompanyName rather than Customers.CompanyName. I changed the delimiter on the column aliases to use double quotes rather than single quotes. I associate single quotes with string constants inside the statement.