SQL умножение на курс валюты

SELECT items.item_id, 
       items.price * ( SELECT rates.rate
                       FROM rates
                       WHERE rates.currency = items.currency
                       ORDER BY rates.date DESC
                       LIMIT 1 ) AS price_in_byn 
FROM items;

SELECT
  i.item_id,
  (i.price * r.rate) AS price_in_byn
FROM
  items AS i
  LEFT JOIN (
    SELECT
      r1.currency,
      MAX(r1.rate) as rate
    FROM
      rate AS r1
      INNER JOIN (
        SELECT
          MAX(r1_1.date) AS max_date,
          r1_1.currency
        FROM 
          rate AS r1_1
        GROUP BY
          r1_1.currency
      ) AS r2 ON r2.currency = r.currency AND r2.max_date = r1.date
      GROUP BY r1.currency
  ) AS r ON r.currency = i.currency