>Can you post the structure of the table(s) involved here to determine when category has subcategories?

Category table

Numero Primary key
Title Character(20)
NoCategory Category primary key

So, basically, this is recursive inside the same table.

So, an unlimited number of categories can have parents and so on.

For most of them, Category.NoCategory is 0 so that denotes a parent. That is the highest hierarchy.

Then, for those records having a value in Category.NoCategory, it means they are child records of the parent. The parent can also be a child of another parent.