如何有效地反转多对多SQL查询？

SELECT students.name, courses.name
FROM students
JOIN enrollments ON students.id = enrollments.student_id
JOIN courses ON courses.id = enrollments.course_id;

WITH product_orders AS (
  SELECT product_id, COUNT(*) as order_count
  FROM orders
  GROUP BY product_id
)
SELECT products.name, product_orders.order_count
FROM products
JOIN product_orders ON products.id = product_orders.product_id
ORDER BY product_orders.order_count DESC;

SELECT departments.name, COUNT(employees.id) as employee_count
FROM departments
JOIN employees ON departments.id = employees.department_id
GROUP BY departments.id
ORDER BY employee_count DESC;

SELECT salesperson_id, sales_amount,
       RANK() OVER (ORDER BY sales_amount DESC) as sales_rank
FROM sales;