Invalid Identifier SQL

Question

So i have this:

SELECT p.plantnaam,o.levcode,o.offerteprijs
FROM plant p, offerte o
JOIN (SELECT plantcode , MIN(offerteprijs) AS offprijs 
      FROM offert         


        

Answer 1

The problem is that you are mixing JOINs. You have both implicit and explicit joins. The explicit JOIN syntax with the ON clause has a higher precedence over the implicit join with the commas. As a result the alias for the plant and the offerte tables will not be available in the ON clause. Try using the same JOIN type throughout:

SELECT p.plantnaam, o.levcode, o.offerteprijs
FROM 
(
  SELECT plantcode , MIN(offerteprijs) AS offprijs 
  FROM offerte
  GROUP BY plantcode
) s
INNER JOIN plant p
   ON s.plantcode = p.plantcode
INNER JOIN offerte o
   ON s.offprijs = o.offerteprijs
ORDER BY p.plantnaam, l.levcode