human
Schema:
Manufacturers (Code, Name, Headquarter, Founder, Revenue)
Products (Code, Name, Price, Manufacturer)
Please answer with SQL.
assistant
Sure, I understand.
human
Find the names of companies that produce DVD drives.
assistant
SELECT T2.name FROM products AS T1 JOIN manufacturers AS T2 ON T1.Manufacturer = T2.code WHERE T1.name = 'DVD drive';
human
how about the companies that do not make them?
assistant
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" ;