CategoryID/ParentCategoryID Looping Help

How do you get away with generating a tab开发者_开发技巧bed list of CategoryID/ParentCategoryID the simplest way? I am no SQL expert, but logically, this is very difficult for me..

Can it be done with 1 or 2 SQL statements, maybe a Do/Loop For/Next would work?

The list should look like this:

Category -Subcategory --SubSubcategory ---InfiniteSubcategories

Category -etc.. --etc...

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Read up on thing called "Closure Tables". It might make few things easier for you.

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This is certainly not an easy problem(if performance is of any importance), so it might be a good idea to read up on some of the solutions that are scattered on the internet.

For a simple(and not at all well suited for tasks where performance is important) you can do this:

function readChildrenNodes(parentNode) {
    newNodes = sql_db.get("SELECT * FROM nodes WHERE parent="+parentNode.id);
    parentNode.appendChildren(newNodes);
    for node in newNodes
        readChildrenNodes(node);
}