yo,
SELECT user.company, user.last_name, user.first_name, user.email, user.city
FROM user
WHERE user.customer = 1
AND user.newsletter = 0
AND user.last <= '2007-01-10'
UNION
SELECT user.company, user.last_name, user.first_name, user.email, user.city
FROM user
INNER JOIN sold ON user.id = sold.userID
AND sold.create >= '2007-01-10'
Ilja