Which tables in the purchasing schema might be able to join, and which columns might be keys to join on?

basic_sql_explore_6.sql

select *
from purchasing.purchaseorderdetail
limit 10;

-- what keys might there be?

\dt purchasing.*

\d purchasing.productvendor
-- productid
-- businessentityid

\d purchasing.purchaseorderdetail
-- purchaseorderid
-- productid

\d purchasing.purchaseorderheader
-- purchaseorderid
-- employeeid
-- vendorid
-- shipmethodid

\d purchasing.shipmethod
-- shipmethodid

\d purchasing.vendor
-- businessentityid