Question

I have a table where i store categories with its parent’s id. Following is the table structure
What i need is to get the parent and details of id 4 in a single query without php recursion

id | CategoryName | parentid
1      Web            0
2      Software       0
3      PHP            1
4      Arrays         3

Answer 1

A self join should be sufficient here. Your goal is to join the table against itself, while relating the parentid of the main row to the id of its parent’s row.

SELECT 
  me.id AS me_id,
  me.CategoryName AS me_category,
  parent.id AS parent_id,
  parent.CategoryName AS parent_category
FROM
  tablename me JOIN tablename parent ON me.parentid = parent.id
WHERE me.id = 4