Table schema:
CREATE TABLE customers (first_name VARCHAR, last_name VARCHAR, id VARCHAR); CREATE TABLE invoices (customer_id VARCHAR)

Question: Find out the top 10 customers by total number of orders. List customers' first and last name and the number of total orders.
SQL: SELECT T1.first_name, T1.last_name, COUNT(*) FROM customers AS T1 JOIN invoices AS T2 ON T2.customer_id = T1.id GROUP BY T1.id ORDER BY COUNT(*) DESC LIMIT 10