CREATE TABLE customer_orders (customer_id VARCHAR2, order_id VARCHAR2)
CREATE TABLE order_items (order_quantity NUMBER, order_id VARCHAR2)
CREATE TABLE customers (customer_id VARCHAR2, customer_name VARCHAR2)

What is the total quantity of products purchased by 'Rodrick Heaney'?
SELECT SUM(t3.order_quantity) FROM customers AS t1 JOIN customer_orders AS t2 ON t1.customer_id = t2.customer_id JOIN order_items AS t3 ON t2.order_id = t3.order_id WHERE t1.customer_name = "Rodrick Heaney"
SELECT SUM("t3"."order_quantity") FROM "customers" "t1" JOIN "customer_orders" "t2" ON "t1"."customer_id" = "t2"."customer_id" JOIN "order_items" "t3" ON "t2"."order_id" = "t3"."order_id" WHERE "Rodrick Heaney" = "t1"."customer_name"