แสดงชื่อเครื่องบินทุกลำที่ John Williams มีใบรับรอง
Show names for all aircrafts of which John Williams has certificates.
df_Aircraft = pd.DataFrame(columns=['name', 'aid']); df_Employee = pd.DataFrame(columns=['eid', 'name']); df_Certificate = pd.DataFrame(columns=['eid', 'aid'])
df_Aircraft[df_Aircraft['aid'].isin(df_Certificate[df_Certificate['eid'].isin(df_Employee[df_Employee['name'] == 'John Williams']['eid'])]['aid'])]['name'].to_list()