แจ้งชื่อลูกค้าที่สั่งซื้อระหว่าง 2009-01-01 ถึง 2010-01-01
Give me the names of customers who have placed orders between 2009-01-01 and 2010-01-01.
df_orders = pd.DataFrame(columns=['customer_id', 'date_order_placed']); df_customers = pd.DataFrame(columns=['customer_name', 'customer_id'])
df_customers.set_index('customer_id').join(df_orders.set_index('customer_id'))[(df_orders['date_order_placed'] >= '2009-01-01') & (df_orders['date_order_placed'] <= '2010-01-01')]['customer_name']