Sql Top Customers Last Quarter

To find your top customers who also bought across multiple categories, filter purchases within 3 months, group by customer, and apply category constraints with HAVING:

SELECT customer_id, SUM(amount) AS total_spent
FROM purchases
WHERE purchase_date >= DATE_SUB(CURDATE(), INTERVAL 3 MONTH)
GROUP BY customer_id
HAVING COUNT(DISTINCT category_id) >= 3
ORDER BY total_spent DESC
LIMIT 5;

This makes sure each customer bought from at least 3 categories. WHERE filters rows before grouping, while HAVING filters groups after.