CREATE TABLE customers (good_or_bad_customer VARCHAR, coupon_id VARCHAR)
CREATE TABLE discount_coupons (coupon_id VARCHAR, coupon_amount VARCHAR)

Are the customers holding coupons with amount 500 bad or good?
SELECT T1.good_or_bad_customer FROM customers AS T1 JOIN discount_coupons AS T2 ON T1.coupon_id = T2.coupon_id WHERE T2.coupon_amount = 500
SELECT "T1"."good_or_bad_customer" FROM "customers" AS "T1" JOIN "discount_coupons" AS "T2" ON "T1"."coupon_id" = "T2"."coupon_id" AND "T2"."coupon_amount" = 500