Log for YSITD

SELECT id as order_id , (SELECT SUM(order_item.quantity * products.price) FROM order_item  INNER JOIN products ON order_item.product_id = products.id  WHERE order_item.order_id = orders.id ) as total FROM orders;

{ "a" : { "b" : 10  } }
{ "a" : { "b" : 8  } }
{ "a" : { "b" : 15  } }