Referrals Within the Same Country

customers.referred_by points to another customer. List every referred customer whose referrer lives in the same country.

Expected output

customer (name), referrer (name), country. Any row order.

Row order is not checked. Column names are not checked; numbers are compared to 2 decimals.

Dataset: E-commerce store

An online store selling electronics, home goods, books, apparel and beauty products to customers in six countries (Jan 2025 to Mar 2026).

customers

One row per registered customer.

customer_id	INTEGER	primary key
name	TEXT
country	TEXT	US, UK, DE, IN, BR or CA
signup_date	TEXT	YYYY-MM-DD
referred_by	INTEGER	customer_id of the referrer, NULL if none

products

Product catalog with current list price.

orders

One row per order. Only completed orders count as revenue.

order_id	INTEGER	primary key, increases with order_date
customer_id	INTEGER
order_date	TEXT	YYYY-MM-DD
status	TEXT	completed, cancelled or returned

order_items

Line items. Revenue of a line = quantity * unit_price (unit_price may include a discount).

order_id	INTEGER
product_id	INTEGER
quantity	INTEGER
unit_price	REAL	price actually charged per unit

Engine: SQLite. Dates are text (YYYY-MM-DD); use strftime(), date() and julianday() for date math.