Użyj tej Wstaw syntax
INSERT INTO ADVNET.dbo.KenCatItemTest
(CategoryItemId,ItemId,CategoryId)
SELECT Newid(),itemid,'0FCA508F-7EB5-4C2E-8803-DE688C4126E5'
FROM janel.dbo.item
WHERE janel.dbo.item.itemnumber LIKE 'c-%'
AND listprice > 0