SQL Server除查询外不返回正确的Asnwer

Question

ALTER PROCEDURE [dbo].[sp_User_not_regestired_companies]
    @userId as int
AS
BEGIN
    select CompanyId, Name  
    from Company

    except

    select CompanyId, Name    
    from SecurityUserCompanyLevel
    where UserId = @userId 
END

我的问题是当我在select子句中写CompanyId时，它将返回正确的答案。当我在select子句中写Name时，它将返回所有公司的列表