The ITEMDETAILS Query gets the most recent Price and last Cost from these two queries
Latest Price
SELECT d.UPC, d.QUANTITY AS LQTY, t.LDATE, d.PRICE AS PPU, d.VAT AS LVAT
FROM Prices AS d INNER JOIN (SELECT UPC, QUANTITY, MAX(EFFDATE) AS LDATE FROM Prices GROUP BY UPC, QUANTITY) AS t ON...