-- Database schema
| Manufacturers : Code [ INT ] primary_key , Name [ TEXT ] , Headquarter [ TEXT ] , Founder [ TEXT ] , Revenue [ INT ] | Products : Code [ INT ] primary_key , Name [ TEXT ] , Price [ INT ] , Manufacturer [ INT ] Products.Manufacturer = Manufacturers.Code |
-- -- What are the names of companies that do not make DVD drives?

SELECT name FROM manufacturers EXCEPT SELECT T2.name FROM products AS T1 JOIN manufacturers AS T2 ON T1.Manufacturer  =  T2.code WHERE T1.name  =  'DVD drive';