Sql Statement trying to understand join statements - sql

Question

My code is pasted here for the Sql tables and information: http://pastebin.com/GsKp4z30
what I am trying to do is:
SuperClean would like to offer a special to their customers that use coupons. Retrieve the names and
addresses for the customers using coupons on any order from September 1, 2014 through December 24,
2014.
But I keep getting 40+ lines of information and I can't seem to get a join statement to work correctly.
I was trying this but I keep getting invalid identifier.
SELECT
CUSTOMER.CUSTOMER_NAME, CUSTOMER_CUSTOMER_NAME, CUSTOMER.CUSTOMER_ADDRESS
FROM CUSTOMER
INNER JOIN
CUSTOMER ON CUSTOMER.CUSTOMER_ID = CUSTOMER_INVOICE.CUSTOMER_ID;

Answer 1

You have a good first attempt.
Your first problem comes from INNER JOIN CUSTOMER - you are already selecting from CUSTOMER, so why JOIN it with CUSTOMER? You should be joining with CUSTOMER_INVOICE instead:
SELECT
CUSTOMER.CUSTOMER_NAME, CUSTOMER.CUSTOMER_ADDRESS
FROM CUSTOMER
INNER JOIN
CUSTOMER_INVOICE ON CUSTOMER.CUSTOMER_ID = CUSTOMER_INVOICE.CUSTOMER_ID;
I've also fixed the other problem with your SELECT, before it was this:
SELECT
CUSTOMER.CUSTOMER_NAME, CUSTOMER_CUSTOMER_NAME, CUSTOMER.CUSTOMER_ADDRESS
Yet there is no column or alias defined as CUSTOMER_CUSTOMER_NAME. So it will throw you an invalid identifier error.
This will return all of the customers with respective customer invoices - now we need to filter it down to invoices with the coupons set to YES using WHERE:
SELECT
CUSTOMER.CUSTOMER_NAME, CUSTOMER.CUSTOMER_ADDRESS
FROM CUSTOMER
INNER JOIN
CUSTOMER_INVOICE ON CUSTOMER.CUSTOMER_ID = CUSTOMER_INVOICE.CUSTOMER_ID
WHERE
CUSTOMER_INVOICE.COUPON_YESNO = 'YES';
and now filter the result-set down further to work with the particular date range from your question. I'll let you figure this part out unless you're having difficulty understanding the WHERE.