Item - has_and_belongs_to_many :orders
Order - has_and_belongs_to_many :items
This is a basic setup for a small shopping app, I can successfully
add/remove/edit a list of items to one or more orders, but now from the
administration i need to be able to perform a search like: "show orders
having (at least) item x and item y and item z (or more)"
Basically, i need to use AND conditions for items belonging to orders,
something like Order.find(:all, :conditions => "items.id = 2 AND
items.id = 5 AND ...", :include => [:items]) .
Obviously the query above doesn't work, but I can't figure out how to do
that.
I think you can do it the other way around, do the find on the items, where the item id is in one of the set. Then the orders you are looking for are the ones in the returned rows as item.order. Then you just need to select the unique orders.