php category, sub category tree

Question

I\'ve done this before in long complicated statements but I\'m trying to clean up some code.

I have the following table structures

parent_categories              


        

Answer 1

The result of INNER JOIN is:

Parent Cat 1 subcategory 1
Parent Cat 1 subcategory 2
Parent Cat 2 subcategory 3

If you want format them as array in array use php