ชื่อและนามสกุลของผู้เชี่ยวชาญที่ทำการรักษาโดยมีค่าใช้จ่ายต่ำกว่าค่าเฉลี่ยคืออะไร?
What are the first name and last name of the professionals who have done treatment with cost below average?
df_treatments = pd.DataFrame(columns=['cost_of_treatment', 'professional_id']); df_professionals = pd.DataFrame(columns=['first_name', 'last_name', 'professional_id'])
below_average_treatments = df_treatments[df_treatments['cost_of_treatment'] < df_treatments['cost_of_treatment'].mean()]['professional_id'] df_professionals[df_professionals['professional_id'].isin(below_average_treatments)]['first_name', 'last_name']