# Find all users who have made at least one transaction

Canonical URL: <https://datadriven.io/problems/find-all-users-who-have-made-at-least-one-transaction-use-e-da64f145>

Domain: SQL · Difficulty: medium

## Problem

Find all users who have made at least one transaction. Use EXISTS with a correlated subquery. Select user_id and username.

## Related

- [All practice problems](https://datadriven.io/problems)
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