order by question - Mailing list pgsql-admin

Hi,All

       for example,I have a query as this 

         select id,product_id from table_name where product_id in (6,3,4,10,7) order by .....

       the results I want to get as bellow:

id................product_id......................

33...............6...................................

40...............6..................................

12...............3....................................

25...............4.................................

10...............4................................

17...............10................................. 

43................7...................................

          any Idea? thanks

--
Tony Liao