Question

The following sql call works fine, returns the correct total retail for customers:

SELECT  customer.id,
        customer.first_name, 
        customer.last_name,
        SUM(sales_line_item_detail.retail) AS total_retail
FROM sales_line_item_detail
    INNER JOIN sales_header 
        ON sales_header.id = sales_line_item_detail.sales_header_id
    INNER JOIN customer 
        ON customer.id = sales_header.customer_id
GROUP BY sales_header.customer_Id
ORDER BY total_Retail DESC
LIMIT 10

However, i need it to return the customers telephone and email addresses as well.. please keep in mind that not all customers have an email address and telephone number. whenever i left join the email and numbers tables, it throws the total_retail amount off by thousands and I am not sure why.

The following query gives completely wrong results for the total_retail field:

    SELECT  customer.id,
        customer.first_name, 
        customer.last_name,
        IF(
            ISNULL( gemstore.customer_phone_numbers.Number), 
            'No Number..', 
            gemstore.customer_phone_numbers.Number
            ) AS Number,
        IF(
            ISNULL(gemstore.customer_emails.Email), 
            'No Email...', 
            gemstore.customer_emails.Email
            ) AS Email,
        SUM(sales_line_item_detail.retail) AS total_retail,
FROM sales_line_item_detail
    INNER JOIN sales_header 
        ON sales_header.id = sales_line_item_detail.sales_header_id
    INNER JOIN customer 
        ON customer.id = sales_header.customer_id
    LEFT JOIN gemstore.customer_emails 
        ON gemstore.customer_emails.Customer_ID = gemstore.customer.ID
    LEFT JOIN gemstore.customer_phone_numbers 
        ON gemstore.customer_phone_numbers.Customer_ID = gemstore.customer.ID
GROUP BY sales_header.customer_Id
ORDER BY total_Retail DESC
LIMIT 10

Any help figuring out why it is throwing off my results is greatly appreciated.

Thanks!

Answer 1

Is it possible that there are multiple records for a Customer_ID in either the customer_emails or customer_phone_numbers tables?