Question

I have a table which have category_id and parent_category_id. How I can get 1 category and 5 sub category by using SQL query.

Suppose table name is : Category

----------------------------------------------------------------
Category ID    |       Parent ID  |     Name     
---------------------------------------------------------------- 
   1           |         NULL     |     Electronics    
   2           |          1       |     Computer   
   3           |          1       |     Calculator   
   4           |          1       |     Mobile
   5           |         NULL     |     Four Wheeler
   6           |          5       |     Cars
   7           |          5       |     Trucks
   8           |          5       |     Jeep
   9           |          5       |     Van

Answer 1

Since MySQL does not support recursive queries/CTEs, you will have to emulate that (which is not, say, straightforward).

Here’s an excellent tutorial on the subject:

http://explainextended.com/2009/03/17/hierarchical-queries-in-mysql/

I will have the decency of not copying the code here 🙂