Running a complex query for every date in a range I've got a table of orders

   Column   |            Type             |                      Modifiers                      
------------+-----------------------------+-----------------------------------------------------
 id         | integer                     | not null default nextval('orders_id_seq'::regclass)
 client_id  | integer                     | not null
 start_date | date                        | not null
 end_date   | date                        | 
 order_type | character varying           | not null


The data has non overlapping standing orders for a client_id and occasionally a temporary order that overrides the standing order on it's start_date when they have a matching client_id. There is application level constraints keeping orders of the same type from overlapping.

 id | client_id | start_date |  end_date  | order_type 
----+-----------+------------+------------+------------
 17 |        11 | 2014-02-05 |            | standing
 18 |        15 | 2014-07-16 | 2015-07-19 | standing
 19 |        16 | 2015-04-01 |            | standing
 20 |        16 | 2015-07-18 | 2015-07-18 | temporary


For example, on 2015-07-18 client 16 has order #20 as it's active order because it overrides the standing order #19. With some fuss I found an efficient way of querying for active order id's on a date.

    SELECT id from (
      SELECT
        id,
        first_value(id) OVER (PARTITION BY client_id ORDER BY order_type DESC) active_order_id
      FROM orders
      WHERE start_date &lt;= ? and (end_date is null OR end_date &gt;= ?)
    ) active_orders
    WHERE id = active_order_id


If you query this with 2015-07-18 as the placeholders, you would get

 id 
----
 17
 18
 20


The query plan on this query compared to some of my other ideas (like sub queries counting the number of temporary orders for a client on a date) is quite small and I'm pretty happy with it. (the design of the table, I'm not thrilled about) 

Now, I need a to find all the active orders for a date range joined with the dates they are active on. For example, with the date range of 2015-07-18 to 2015-07-19 I would like the following result.

active_date | id 
------------+----
 2015-07-18 | 17
 2015-07-18 | 18
 2015-07-18 | 20
 2015-07-19 | 17
 2015-07-19 | 18
 2015-07-19 | 19


Order 20 overrides order 19 on 2015-07-18 but not on 2015-07-19.

I found with generate_series() I can generate a range of dates, but I haven't a clue how to join that with this to get a table of dates and order id's. My hunch is a cross join but I can't figure out how to make that work in this circumstance.

Thanks

UPDATE
Added an sql fiddle.
I would use select distinct on instead of window function, then just join the days.

select 
    distinct on (date, client_id) date, 
    id 
from orders
inner join generate_series('2015-07-18'::date, '2015-07-19'::date, '1 day') date
  on start_date &lt;= date and (end_date is null or date &lt;= end_date)
order by date, client_id, order_type desc


http://sqlfiddle.com/#!15/5a420/16/0

I can elaborate more if something is not clear.