how do i select this list

The query below gives me a list of usernames with the highest point score at the top. There is also a secondary points list which i need to use to rank players if there POINTS are the same. ie: username points margin paul 26 24 mark 23 11 john 23 10 I want to rank 'john above 'mark' as his margin points are lower. I can't rank by margin alone and i need ranking by points (Desc) first then by lowest margin. how can i change this statement below to achieve this. Thanks $query = mysql_query("SELECT * FROM leaderboard WHERE comp_id = $comp_id ORDER by points DESC ");