Question

I’m building a website with PHP & mySQL.
In my application, the categories of products are stored as hierarchy in DB.
I followed the approach of “Materialized path” (aka “Flat table Model”) & created a table like this :

Suppose I want to build a breadcrumb for items in category FLASH (category_id=8) :

ELECTRONICS -> PORTABLE ELECTRONICS -> MP3 PLAYERS -> FLASH

I wonder if I could get the line of ancestry from ‘FLASH’ IN CORRECT ORDER by this query:

Select * from category where category_ID in (1,6,7,8) ORDER BY '1,6,7,8'

What can be the correct replacement for :

ORDER BY '1,6,7,8'

? Thanks for all suggestions !

Answer 1

I found the answer my own !

SELECT * 
FROM category
WHERE category_ID
IN ( 1, 6, 7, 8 ) 
ORDER BY category_ID =1 DESC , category_ID =8 DESC , category_ID =7 DESC , category_ID =6 DESC 

The SQL string above can help me to sort ID by any predefined order : 1-6-7-8 or 1-8-7-6 or 6-1-8-7 or any thing else !