Question

Create a stored procedure called sp_del_inactive_cust to delete customers that have no orders. The stored procedure should delete 1 row.

Here is the database I am working with.

_{(source: bcitwebdev.com)}

My immediate thought is that I need to check the customers table against the orders table. If the customer is present in the customers table but not in the orders table, that must mean that they have not created any order ids under their customer id. Then, I must delete the customer if they do not have any orders.

I’m not really sure how to go about scripting this problem. I need help! Please keep it simple as I am a first semester student.

Here’s something I’ve tried starting:

CREATE PROCEDURE     sp_del_inactive_cust
AS
SELECT               customers.customer_id,
                 orders.customer_id
FROM         customers
INNER JOIN           orders ON customers.customer_id=orders.customer_id
WHERE        /* customer_id is found in customers table but not in orders table */

And then I will execute the procedure.

This question has been answered thanks to the help of Michael Fredrickson.

Here are the final statements which deleted the required 1 row:

CREATE PROCEDURE        sp_del_inactive_cust
AS
DELETE                  customers
FROM                    customers
LEFT OUTER JOIN         orders ON customers.customer_id = orders.customer_id
WHERE                   orders.customer_id IS NULL;
GO

EXECUTE                 sp_del_inactive_cust;
GO

Answer 1

CREATE PROCEDURE sp_del_inactive_cust

AS

DELETE TOP (1) c
FROM
    customers c
    LEFT OUTER JOIN orders o
        ON C.customer_id = o.customer_id
WHERE
    o.customer_id IS NULL