How are you associating the rooms content type to the reservations one? If you're using entity reference, then you would want to create a relationship with the reservations content type through that reference field. Make sure you don't check "require this relationship" then add a filter so that the related node (reservations) nid is NULL.

The other option is in a custom module, using hook_views_query_alter. Load the reserved room nids, through a normal DB query, then add a NOT IN condition to the list of nids. Here's the documentation on that hook:

https://api.drupal.org/api/views/views.api.php/function/hook_views_query_alter/7

Jamie Holly
http://hollyit.net
On 1/19/2015 9:37 AM, Lluís Forns wrote:
I have a site with 2 content types: rooms and reservations. I want to list all the rooms without a reservation for an interval, and also for services, capacity, ....

I tried creating a view with a PHP filter to check free rooms, but then if the page lists 10 rooms, sometimes there are 7, 2, or 0; because the filter lists the 10 rooms and after remove the occupied ones.

I have tried to create a "subview" filter to select nodes "not in (view of occupied rooms); but I haven't find a way to do so.

Any idea of how to accomplish this?

thanks
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