How to build menu with single query?

[eluser]Johan André[/eluser]
You can build trees in databases in various ways:

1. Adjacency List - this is using parent_id pointing to the parent (doh!). Not possible to fetch the tree using one query.

2. Modified Preorder Tree Traversal - this tree is "harder" to update but lightning fast at fetching. This is the one you should use when getting a menu with multiple levels in just one query.

Check out the forum. There is something called MPTTree that does just this...