Need Search Engine tips - got any?

[mmosel]

Hi all, I hope all is well,

I'm just beginning to write my site's advanced search engine. I've checked out the full-text search engine tutorial and it's great - no problem there. I can easily grasp how to write a basic search engine. However, my needs are a bit more complex.

For example: I have a table full of products. In this table I have ids for three external tables that will need to be included in the advanced search. I have an artists table, a media type table, and two category tables.
For the artist and media table, I can simply query the tables for the id and then include the id in my search of the product table.

Where I think I need help is with my categories. You see, I have a many to many table inbetween my products and my categories table. It get's tricky with my category table itself, because I have three levels of categories.
As an example, my category table kinda looks like this:

id | cat_name | level2_id | level3_id

So, If I was only searching for a top level category, with an id of 7, I could search the many-to-many products_categories table for all products that match id 7. (I guess I would have to join the many-to-many table with the products table? Not sure about this) - However, the above results would be limited because they wouldn't include any of the sub or sub-sub category ids! So, for a thorough search of all products in a top category, I might have to search for matches of 50 or more category ids! So I need to some how be able to tie in the search through the category tables and then the search through the many-to-many table and then finally combine that with the search of the products table itself. Did I lose you yet?

Can you see how I might be a little confused here? Any tips or suggestions to point me in the right direction?

-mmosel