CREATE TABLE customer_orders (order_id VARCHAR, order_status VARCHAR)
CREATE TABLE order_items (order_quantity INT, order_id VARCHAR)

What is the total number of products that are in orders with status 'Cancelled'?
SELECT SUM(t2.order_quantity) FROM customer_orders AS t1 JOIN order_items AS t2 ON t1.order_id = t2.order_id WHERE t1.order_status = "Cancelled"
SELECT SUM("t2"."order_quantity") FROM "customer_orders" AS "t1" JOIN "order_items" AS "t2" ON "t1"."order_id" = "t2"."order_id" WHERE "Cancelled" = "t1"."order_status"