Processing hierachical data in SQL

[eluser]Dam1an[/eluser]
I've seen several posts lately about dealing with hierachical data, and this is the best resource I've found on the subject, so thought a few others might find it useful.

One thing about the nested set model, is that if you plan on inserting/deleting a lot of data, then you could find yourself changing a lot of pointers (the left and right values) so its best for stuff which doesn;t change too much

Anybody else got any good resources for this stuff?

Just found another good looking explanation with examples via sitepoint