$query =
qq|SELECT
c.id AS customer_id, c.name, c.street, c.zipcode, c.city,
- c.country, c.department_1, c.department_2, c.email
+ c.country, c.department_1, c.department_2, c.email, c.customernumber
FROM dunning d
LEFT JOIN ar ON (d.trans_id = ar.id)
LEFT JOIN customer c ON (ar.customer_id = c.id)