Question

Consider a table like this:

   folders_table
   -----------------------
      INT id_folder
      INT id_folder_parent
      VARCHAR folder_name

Which stores a simple directory structure. How could I get all subdirectories of a directory with a single SELECT query?

Answer 1

It is possible, but you need to change your database structure; once the changes are made, you can retrieve a tree of any depth in one query. The queries are slightly more complex, but it’s still pretty straightforward.

• Storing Hierarchical Data in a Database (SitePoint) – this article is step by step, very clear.
• Managing Hierarchical Data in MySQL – not as clear as the above.