Get my Friends list from another tables

I am stuck on the issue of friends list

i have two tables First

1- Users table (ID, username, Password)

2- Friends table (id, myid, friend_id)

now if i have two users in users table - First user id = 50 - Second user id = 56

and at same time i have in the friends table one record ID=1 myid=50 friend_id = 56

i want to create query and this query ( if i login and my id is 50 ) it will show me only username of 56 user and also if i login with user id 56 it will show me the username of 50 user

i know there will be two query first will bring all my friends with my id and second will show my friends without my id but i don't know how pls help

some if my code

function get_myfriends(){
    $this->db->where('myid',$this->session->userdata('userid'));
    $this->db->or_where('fid',$this->session->userdata('userid'));
    $query = $this->db->get('myfriends');
    return $query->result();    
}

function get_user_by_id($id){
    $this->db->where('userid',$id);        
    $query = $this->db->get('users');
    foreach ($query->result() as $row){

        // Here is the problem
        if($row->myid == $this->session->userdata('userid'))

        }else{
        }
    return $query->result();
}

I think you should make friends relation in both sides, for example if user 50 and user 56 are both friends to establish this relationship you should insert 2 entries in myfriends table:

+------+-----+
| myid | fid |
+------+-----+
|   50 |  56 |
|   56 |  50 |
+------+-----+

and then to get all friends for any user you can simply do it by: $sqlQuery = 'SELECT * FROM myfriends JOIN users ON myfriends.fid = users.userid WHERE myfriends.myid = ?'; return $this->db->query($sqlQuery, $id)->result();

Update

if you want it only one side relation you can try this query: $sqlQuery = 'SELECT * FROM myfriends JOIN users ON (myfriends.fid = users.userid OR myfriends.myid = users.userid) AND user.userid <> ?'; return $this->db->query($sqlQuery, $id)->result();