SELECT p.name,DATEDIFF(CURRENT_DATE,p.created_at) age_days,COUNT(t.id) sales,AVG(tsl.unit_price_before_discount) avg_cost,STDDEV(tsl.unit_price_before_discount) cost_variability FROM products p JOIN transaction_sell_lines tsl ON p.id=tsl.product_id JOIN transactions t ON tsl.transaction_id=t.id WHERE t.type="sell" GROUP BY p.id,p.name,p.created_at ORDER BY age_days;