select p1.name,p2.name,p3.name as friends from friend as f1 join friend as f2
on f2.userid!=f1.userid and f2.friendid = f1.friendid
join  user1 as p1 on p1.id = f1.userid
join  user1 as p2 on p2.id = f2.userid
join  user1 as p3 on p3.id = f2.friendid
order by f1.userid,f2.userid;

........................./mutual friend