I have a table named PRODUCTS with 3 columns for three different categories, i want to select all products which have any of the 3 values in any of the 3 columns.
What i'm trying to do is show related products based on any of the 3 categories.

Example table:

> 
> id,name,cat1,cat2,cat3
> 
> 
> 1,Keyboard,2,8,4  
> 
> 2,Mouse,2,NULL,NULL  
> 
> 3,Monitor,16,2,NULL
> 
> 
> 

Let's supose i'm viewing ITEM id=1, i want to do a query to show the other 2 products that have category number 2 in any of the 3 columns.

How do I do that?

Thank you very much,
Andres