SQL Quest › SQL Interview Questions › Joins

Users Who Never Sent Money

MediumFreeQuerying BasicsJoinsNULL Handling

The anti-join: find the people a table does NOT mention. Peer-to-peer sends are rows in transactions with type = 'transfer_out'. List the users who have never sent one, whatever its status.

Return user_id, country, plan and signup_date from users. Order by signup_date ascending, then user_id ascending.

Solve it in the browser editor →

Runs on SQLite in your browser, graded against the expected result, no signup. A wrong answer gets a diagnosis, not just "incorrect".

Schema

users

user_id	signup_date	country	home_currency	plan	plan_since	kyc_verified_at	referred_by	birth_year
1	2025-06-01	IE	EUR	standard	2025-06-01	2025-06-03 16:00:00	NULL	1972
2	2025-06-02	FR	EUR	standard	2025-06-02	2025-06-04 16:00:00	NULL	1979
3	2025-06-03	GB	GBP	standard	2025-06-03	2025-06-08 04:00:00	NULL	1977

transactions

txn_id	user_id	ts	type	amount	currency	amount_gbp	fee_gbp	merchant_category	merchant_country	counterparty_user_id	status	decline_reason
1	1	2025-06-14 11:01:51	fx_exchange	32271.15	JPY	167.81	1.68	NULL	NULL	NULL	completed	NULL
2	1	2025-06-14 11:17:45	bill_payment	59.53	EUR	50.6	0	utilities	IE	NULL	completed	NULL
3	7	2025-06-16 10:06:38	card_payment	122.27	EUR	103.93	0	shopping	ES	NULL	completed	NULL

Expected output: user_id=1, country=IE, plan=standard, signup_date=2025-06-01 ...

Hint

LEFT JOIN transactions t ON t.user_id = u.user_id AND t.type = 'transfer_out' — the type condition goes in the ON clause, not WHERE, or the LEFT JOIN turns into an inner one. Then WHERE t.txn_id IS NULL.

Concepts

SELECT LEFT JOIN NULL Handling WHERE Anti-Join

Practise the topic: SQL practice questions · JOIN practice · NULL handling practice

In these company practice sets

Revolut

A SQL Quest challenge matched to patterns reported for these companies — not a question any of them has published.

Users Who Never Sent Money

Schema

Hint

Concepts

In these company practice sets

Related questions