I have 3 tables called:
There is no way to do it in a DB-agnostic way. So you need to get the whole data-set like this:
select r.name as ResName, a.name as AppName from Resouces as r, Applications as a, ApplicationsResources as ar where ar.app_id = a.id and ar.resource_id = r.id
Adn then concat the AppName programmatically while grouping by ResName.