Case 3: Duplicated Orders

SELECT user_id, SUM(amount) AS total_spent
FROM orders 
INNER JOIN users ON orders.user_id = users.id
WHERE status = 'Active' 
GROUP BY user_id;

-> Hash Aggregate (user_id)
  -> Hash Join (orders.user_id = users.id)
    -> Filter (users.status = 'Active')
      -> Seq Scan on users
    -> Seq Scan on orders