select productname, Pr.categoryid, unitprice, categoryname, companyname, Pr.supplierid
-- selecteren van welke tabellen we weergeven
from production.products as Pr inner join production.Categories as Ca
-- de tabellen even anders benamen
on Pr.categoryid = Ca.categoryid
-- kijken of er een link is tussen de products en categories velden
inner join Production.Suppliers as Su
-- kijken of er nog een supplier id hit is met de producten
on Pr.supplierid = Su.supplierid
 --------------------------------------------------
select companyname, orderdate, region, city, address
from [Sales].[Customers] as SC left outer join [Sales].[Orders] as SO
on SC.custid = SO.custid
where orderdate is null
order by orderdate