SQL gyakorlás

SELECT
  o.productCode,
  (
    SELECT
      p.productName
    FROM
      products p
    WHERE
      p.productCode = o.productCode
    LIMIT
      1
  ) as Név,
  o.priceEach,
  count(*) as Darab,
  sum(o.priceEach) as Összeg,
   avg(o.priceEach) as Átlag
FROM
   orderdetails o
GROUP BY
   o.productCode
ORDER BY
   o.productCode