Feature request from CRYX2, posted on GitHub Sep 16, 2015
Hello, I've not found any options to use multiple selection (for the same attribute) for layered navigation. In Magento 1 this options was very frustrating, now is implemented?
We plan on implementing this in the near term after our GA launch. Internally we're tracking it as (MAGETWO-39787) to enhance our layered navigation. Those enhancements include a category element ( to drill down via category ), multi-select (effectively or) within an attribute, and adding category to advanced search form.
While there are extensions that provide this, it would be good to have this a core feature.
One part of this feature that gets forgotten is to make it a choice whether the multi-select is an OR (increasing the number of options - useful for Colour or Size) or AND (decreasing options - useful for restrictions like Food Intolerances)
I would love to have the possibility to add a multiselect attribute to the layered navigation that can either have a OR or AND functionality. But I think that it is not possible with the current magento search framework. The current version of the search framework gets a SearchCriteriaInterface (which would support such a feature) and discards all search groups (which makes complex queries including an top level OR statement impossible) and when a field is declared multiple times in the search criteria, it just uses the last occurrence.