ALTER TABLE "product-printproducts"
  DROP COLUMN IF EXISTS listprice,
  ADD listprice INT NOT NULL DEFAULT 0;

UPDATE "product-printproducts"
SET listprice = ROUND(price)
FROM (
       SELECT
         printid,
         price * COALESCE(pricepremium, 1) * 100
         * CASE printproducts.groupid
           WHEN 2
             THEN 0.2 -- 0.2m2 is the minimum paid size for canvas
           ELSE 1 END AS price -- 1.0m2 is the same for wallpaper
       FROM "product-printproducts" printproducts
         JOIN "product-products" products ON printproducts.productid = products.productid
         JOIN (
                SELECT
                  groupid,
                  MIN(price) AS price
                FROM "product-printprices"
                GROUP BY groupid
              ) prices ON printproducts.groupid = prices.groupid
         LEFT JOIN (
                     SELECT
                       designerid,
                       1 + (pricepremium / 100) AS pricepremium
                     FROM designers
                   ) designers ON products.designerid = designers.designerid
     ) s
WHERE "product-printproducts".printid = s.printid;