gistfile1.sql

SELECT ISNULL(NULLIF(ca.Value, ''), cc.Email) AS 'Company', 
    SUM([OrderTotal]) as Total,
	SUM([OrderTotal]-RefundedAmount) as AdjustedTotal 
FROM [dbo].[Nop_Order] oo
INNER JOIN Nop_Customer cc on oo.CustomerID = cc.CustomerID
LEFT OUTER JOIN Nop_CustomerAttribute ca on cc.CustomerId = ca.CustomerId and ca.[Key] = 'Company' 
WHERE RefundedAmount < OrderTotal
AND OrderTotal > 0 
GROUP BY ISNULL(NULLIF(ca.Value, ''), cc.Email)
ORDER BY AdjustedTotal  DESC