ค้นหานามสกุลของผู้ติดต่อคนแรกขององค์กรที่มีหมายเลข UK Vat สูงสุด
Find the last name of the first ever contact person of the organization with the highest UK Vat number.
df_organizations = pd.DataFrame(columns=['organization_id', 'uk_vat_number']); df_individuals = pd.DataFrame(columns=['individual_last_name', 'individual_id']); df_organization_contact_individuals = pd.DataFrame(columns=['organization_id', 'individual_id', 'date_contact_to'])
org_id = df_organizations[df_organizations['uk_vat_number'].idxmax()]['organization_id']; contact_id = df_organization_contact_individuals[df_organization_contact_individuals['organization_id'] == org_id].sort_values('date_contact_to')['individual_id'].iloc[0]; df_individuals[df_individuals['individual_id'] == contact_id]['individual_last_name'].iloc[0]