พนักงานชื่อเอลซ่าอาศัยอยู่ที่ไหน?
Where does the staff member with the first name Elsa live?
df_staff = pd.DataFrame(columns=['address_id', 'first_name']); df_address = pd.DataFrame(columns=['address', 'address_id'])
df_staff.merge(df_address, on='address_id')[df_staff['first_name'] == 'Elsa']['address']