Confusing title, and confusing problem..
Here's the thing:
I have 2 main categories (Topic (cat_id = 3) and Source (cat_id = 13)), each category having about 5 subcategories (Let's say SubTopic 1 to 5 (parent cat_id = 3) and SubSource 1 to 5 (parent cat_id = 13)).
Every post has one SubTopic category, but possibly multiple SubSource categories.
What I want is the possibility to check, for every SubTopic the available SubSource according to all posts that have the same SubTopic..
- Post A has SubTopic 1 and SubSource 1 + SubSource 2
- Post B has SubTopic 1 and SubSource 5
- Post C has Subtopic 2 and SubSource 1 + SubSource 4
What I want to know is what to display is (I don't care about which posts, just the SubSource categories):
- Subtopic 1 has Subsource 1 + SubSource 2 + SubSource 5
- Subtopic 2 has Subsource 1 + SubSource 4
Is there an easy way (or even a hard one) to get this? I really can't see how..
Any help would be much appreciated! Thanks!