Which SQL query finds the top 3 customers by total order value from an orders table?

• A. SELECT customer_id, SUM(order_value) AS total FROM orders GROUP BY customer_id ORDER BY total DESC LIMIT 3;
• B. SELECT TOP 3 customer_id, SUM(order_value) AS total FROM orders GROUP BY customer_id ORDER BY total DESC;
• C. SELECT customer_id, MAX(order_value) FROM orders GROUP BY customer_id;
• D. SELECT customer_id, SUM(order_value) AS total FROM orders ORDER BY total DESC LIMIT 3;

Answer: (A)

To get the top spenders, you first need to sum up how much each customer spent across all their orders, then pick the three highest totals. The best query does exactly that: it groups rows by customer_id, calculates SUM(order_value) as total for each customer, orders the results by that total in descending order, and then limits the output to 3 rows. This yields the three customers with the largest combined order value.

Using TOP instead of LIMIT can work in some SQL dialects, but it isn’t as portable across databases. Using MAX(order_value) would return only the largest single order per customer, not the total across all orders. And omitting GROUP BY would not produce per-customer totals and may cause an error since you’re aggregating without grouping the customer_id.