Question

Ok so I have a table called categories that looks like this:

id       name      parent_id
1        camera    null
2        computer  null
3        digital   1
4        gps       null
5        laptop    2

I want to be able to return computer -> laptop or camera -> digital when I query id = 3 or 5.

Any ideas?

Answer 1

Use a self left join :

select a.name, b.name as parent_name from categories a left join categories b on a.parent_id = b.id where a.id in (3,5);

Above query is valid for getting a one level of parent. If you want to traverse through the whole lineage please refer the following link. They have listed down few standard ways of traversing tree :

http://jan.kneschke.de/projects/mysql/sp/