this is the default entry in the 1.5.1 install:

SELECT DISTINCT c.customers_email_address as customers_email_address, c.customers_lastname as customers_lastname, c.customers_firstname as customers_firstname FROM TABLE_CUSTOMERS c LEFT JOIN TABLE_ORDERS o ON c.customers_id=o.customers_id WHERE o.date_purchased IS NULL

this returns all customers that have not yet made a purchase.

my objective was exacly this but to only return customers that registered 1 week ago i.e between -14 days and -7 days period.