UPDATE product
SET price = 12.95
WHERE product_id in
(SELECT product_id
FROM product_to_category
INNER JOIN category
ON product_to_category.category_id = category.category_id
WHERE category.parent_id = 39)
UPDATE product
SET price = 12.95
WHERE product_id in
(SELECT product_id
FROM product_to_category
INNER JOIN category
ON product_to_category.category_id = category.category_id
WHERE category.parent_id = 39)