I have two QVD (Product_Price_History and Order_Product) Can I make a new QVD from the data in these two QVD, as in SQL
SQL
select op.*,(select price_purchase from `s_product_price_history` ph where op.`product_id`=ph.`product_id` and ph.`date_added`<op.`insert_date` order by ph.`date_added` desc limit 1) as price_purchase