Showing list of rows not found in a 2nd list

[tghounsell]

I have lists of boats, members and docks. I have the three lists joined in a separate list of members_boats_docks. However, I want to make a list of docks that are not currently occupied, and therefore, not currently listed in the members_boats_docks list.

One way to do this would be to simply put the database joins in the docks table and eliminate the members_boats_docks list. However, there are other times where members have boats and no docks, so keeping this relationship in the docks table doesn't really make sense. I could also put a member join in boats and a boats join in docks, but there are other times where I would like to list data from all three lists. So, I'm not sure of the best way to configure the relationships between the tables or how, with the current configuration, I can show a list of docks that have no boat relationship.

Suggestions much appreciated.

 

[lousyfool]

... how, with the current configuration, I can show a list of docks that have no boat relationship.

From what I understand, the simplest way to do so with your current setup should be e.g. to create a new menu item for your existing joined list with pre-filters set so only "docks without boats" are displayed. In the menu item config you can also limit the elements to be displayed (as you might not need them all for the purpose), etc.