SQL - Best practice for a Friendship table

Question

Before you show me duplicates, please note that I\'ve searched through the site an have found some examples but not quite specific to my prob

Answer 1

Quassnoi wrote an article explaining why you might want to have a version of the table with two rows per pair, to make queries easier: http://explainextended.com/2009/03/07/selecting-friends/

(the article talks about MySQL but it is worth bearing in mind as a performance technique for any SQL database)