จำนวนสั่งซื้อผลิตภัณฑ์ภาพถ่ายทั้งหมดคือเท่าใด
What are the total order quantities of photo products?
order_items = pd.DataFrame(columns=['Order_Quantity', 'Product_ID']); products = pd.DataFrame(columns=['Product_ID', 'Product_Name'])
pd.merge(order_items, products, on='Product_ID')[products['Product_Name'] == 'photo']['Order_Quantity'].sum()