การใช้ Join ร่วมกับการรวมข้อมูล

WITH orders AS (SELECT
o.order_id,
item.product_id
FROM ecommerce.ecomm_orders o, unnest(o.order_items) item)

SELECT 
	p.product_id,
	COUNT(o.order_id)
FROM orders o
-- Complete the join to the products table
___ ecommerce.ecomm_products p
-- Join the data using the product_id column
___
GROUP BY p.product_id;