Question

i have two tables in my database one is to keep users info (users_table )
and the other one keeps track of the friends

users_table:

id    username      avatar  
1         max       max.jpg  
2         jack      jack.jpg  

friends_table :

id    u1_id      u2_id  
1         1          2  
2         1          3  

in every user profile i show his/her friends list

here is my query

select u.id,
    u.username,
    u.avatar
from friends_table f
join users_table u on f.u1_id = u.id || f.u2_id = u.id
where u.id <> $profile_id
    and (f.u1_id = $profile_id || f.u2_id = $profile_id)

this query selects friends of the profile owner ($profile_id)

and join them with the user table to get each friend username and avatar

now i want to count the mutual friends between each friend and the profile owner is it possible to this in one query or should i do some long and probably slow query like this for each founded friend( it’s just a example and it might have some syntax error ):

       foreach ( $friends_list_query_resul as $qr ){
       $friend_id = $qr['id'];

       $mutual_count = mysql_query
    ( "select count(*) from friends_table where 
    ($u1_id = $friend_id || $u2_id = $friend_id )
               && 


    ( $u1_id IN ( SELECT `u1_id`,`u2_id` from friends_table where
     ($u1_id = $profile_id || $u2_id = $profile_id ) )

||

      $u2_id IN ( SELECT `u1_id`,`u2_id` from friends_table where
     ($u1_id = $profile_id || $u2_id = $profile_id ) )


       ")
        }

Answer 1

i’ve decided to add two rows for each friend relation to the table .

id    u1_id      u2_id  
1         10         20  
2         20         10

it makes the process easier and faster .