Is there a simple way to query the children of a node?

Question

I\'ve been using the crap out of the Nested Set Model lately. I have enjoyed designing queries for just about every useful operation and view. One thing I\'m stuck on is how

Answer 1

It seems to me this should be easily doable without the subqueries or parent column redundancy! For example, given parent's left and right are already known:

SELECT child.id
FROM nodes AS child
LEFT JOIN nodes AS ancestor ON
    ancestor.left BETWEEN @parentleft+1 AND @parentright-1 AND
    child.left BETWEEN ancestor.left+1 AND ancestor.right-1
WHERE
    child.left BETWEEN @parentleft+1 AND @parentright-1 AND
    ancestor.id IS NULL

That is, “from all descendents of the node in question, pick ones with no ancestor between themselves and the node”.