SELECT cu.customer_name, cu.customer_nr,
COUNT(c.au) AS orders,
SUM(c.costs) as costs,
SUM(c.material) as material,
(SUM(c.sales) - SUM(c.credit) - SUM(c.discount)) as sales,
SUM(c.result) as result
FROM v_calculation c
JOIN v_customer cu ON c.au = cu.au
WHERE cu.au != ''
AND c.month BETWEEN '' AND ''
GROUP BY cu.customer_nr
ORDER BY (SUM(c.sales) - SUM(c.credit) - SUM(c.discount)) DESC
