select d.CatalogNo,d.Manufacturer,d.Name, sum(quantity)
from DeviceInstance di
full join Device d
on d.Id=di.DeviceId
group by di.DeviceId

Column 'Device.CatalogNo' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

group by d.DeviceId, d.CatalogNo,d.Manufacturer,d.Name

select d.CatalogNo,d.Manufacturer,d.Name, sum(quantity)
from DeviceInstance di
full join Device d
on d.Id=di.DeviceId
group by d.Name, d.CatalogNo,d.Manufacturer