ค้นหาชื่อบริการที่ไม่เคยใช้
Find name of the services that has never been used.
df_services = pd.DataFrame(columns=['service_name', 'service_id']); df_party_services = pd.DataFrame(columns=['service_id'])
df_services[~df_services['service_id'].isin(df_party_services['service_id'])]['service_name']