ลูกค้าที่ถือคูปองมูลค่า 500 เสียหรือดี?
Are the customers holding coupons with amount 500 bad or good?
df1 = pd.DataFrame(columns=['coupon_id', 'coupon_amount']); df2 = pd.DataFrame(columns=['good_or_bad_customer', 'coupon_id'])
pd.merge(df1[df1.coupon_amount == '500'], df2, on='coupon_id')['good_or_bad_customer']