SELECT DISTINCT
  c.name AS customer,
  c.country,
  c.tier
FROM customers c
JOIN orders o ON c.cust_id = o.cust_id
JOIN order_items oi ON o.order_id = oi.order_id
JOIN products p ON oi.product_id = p.product_id
JOIN categories cat ON p.cat_id = cat.cat_id
WHERE cat.name = 'Electronics'
ORDER BY c.name;