<?php
public function get_post($id) {
    $query = $this->db->get_where('posts', array('id' => $id));
    if ($query->num_rows() > 0) {
        $data = $query->row();
                // run separate query for author name
                $author_query = $this->db->get_where('authors', array('id' => $data[author_id]));
                if ($author_query->num_rows() == 1) {
                    $author = $author_query->row();
                    $data['first_name'] = $author['first_name'];
                    $data['last_name'] = $author['last_name'];
                } else {
                    $data['first_name'] = 'Unknown';
                    $data['last_name'] = 'Unknown';
                }
                return $data;
    }
}