SELECT model_name FROM chip_model EXCEPT SELECT chip_model FROM phone WHERE Accreditation_type  =  'Full'
Find the names of the chip models that are not used by any phone with full accreditation type.
SELECT model_name FROM chip_model EXCEPT SELECT chip_model FROM phone WHERE Accreditation_type = 'Full '
select model_name from chip_model except select chip_model from phone where accreditation_type = value
Find the names of the chip models that are not used by any phone with full accreditation type .