[SOLVED] PHP retrieve distinct data from database based on two rows

PHP retrieve distinct data from database based on two rows

I have table named messages with some rows:

+---------+
| columns |
+---------+
| id      |
| from    |
| to      |
| body    |
| date    |
+---------+

What I want is to retrieve a list of users I message or users who messaged me.

public function get_users_m($where)
{
    $this->db->select('*');
    $this->db->from('messages');
    $this->db->where($where); // to = my_id or from = my_id 
    $this->db->group_by('from, to');

    return $this->db->get()->result_array();
}

I made that using Codeigniter but the problem is when I reply, for example to C, I get A (me) send message to C and C send message to A and I don't want that I want just C one time because it doesn't matter if i'm the one who sent him message or he is the one who send me the message it still the same user.

Solution

What about this

public function get_users_m()
{
    $my_id = 5; # some id
    $this->db->select('*');
    $this->db->from('messages');
    $this->db->where('from == $my_id');
    $this->db->or_where('to == $my_id'); # add this or_where Clause
    $this->db->group_by('user_id');
    $query = $this->db->get();
    $result = $query->result_array();
    return $result;
}

Check comment of Tpojka