CREATE TEMP TABLE customer_ids ON COMMIT DROP AS
    SELECT DISTINCT customer_id FROM orders
    WHERE payment_status IN (1,300) AND
          date_ordered BETWEEN '06/26/2011' AND '07/02/2011' AND
          customer_id != 0;

CREATE INDEX tmp_cid_idx ON customer_ids (customer_id);
ANALYZE customer_ids;

CREATE TEMP TABLE last_orders ON COMMIT DROP AS SELECT id, customer_id, date_ordered FROM orders
    WHERE payment_status = 1 AND
          date_ordered BETWEEN '6/1/2010' AND now() AND
          customer_id IN (SELECT customer_id FROM customer_ids);

--Then one of the following
SELECT o.id, o.customer_id, o.date_ordered, f.print_group_id, f.item_id, f.cost
FROM last_orders o
INNER JOIN files f ON o.id = f.order_id AND f.page = 1;

--OR
CREATE TEMP TABLE last_files ON COMMIT DROP AS
    SELECT order_id, print_group_id, item_id, cost
    FROM files
    WHERE order_id IN (SELECT id FROM last_orders);