Question

I have one table that looks something like this:

id  parent_id    name
1   0            page #1
2   1            Page #2
3   1            Page #3
4   2            Page #4

*parent_id* is realated to id.

page #4 is a child of page #2
and page #2 is a child of page #1
and so is page #3.

I need a mysql query that can get all children to, say id 1.
Which would return all these pages since all pages “master parent” (lol) is page #1.

Answer 1

You basically have two options:

• Using recursion, either in your application logic or in the query, if your RDBMS supports that

• Storing left/right values for each node in your tree, which lets you easily find all the sub-tree of a node

Both those options are covered in an excellent article at sitepoint, http://www.sitepoint.com/hierarchical-data-database/ (but it doesn’t cover RDBMS recursion, which yours probably don’t support anyway)