ค้นหาชื่อพยาบาลที่โทรมา
Find the names of nurses who are on call.
df_on_call = pd.DataFrame(columns=['nurse']); df_nurse = pd.DataFrame(columns=['name', 'EmployeeID'])
df_nurse[df_nurse['EmployeeID'].isin(df_on_call['nurse'])]['name'].drop_duplicates()