mysql tree structure - count problem

[strrev]

Hi guys,

I'm using this method : http://www.sitepoint.com/article/hierarchical-data-database/2/

I will make you a JPG to describe you want i want to do .

So , this is the structure : http://sitepointstatic.com/graphics/sitepoint_numbering.gif

And this is what I want to do : http://i37.tinypic.com/4tt6om.gif

In mysql i have 4 fields : level_id , order_id , left_id and right_id .

I have too a field real_order_id in wich i need to store the values from Jpg number 2.

I can calculate the number of childreens using ( right_id - left_id - 1 ) \ 2 .

Anyone have an idea ? 🙂 .

Thanks,