Question

For example, if I run one query in model:

public function list_users() { 
       $q = "SELECT user_id, username FROM users";
       return $q->result_array();
}

And now, to lists posts from that user, I need to refer to it’s id within this function:

   public function list_posts() { 
           $q = "SELECT post_id, post_title, post_content FROM posts 
                 WHERE user_id = what??";
           return $q->result_array();
   }

OK both of these functions are in Model. Now, How to use RESULT from list_users() in list_posts(). Please have in mind that I need to pass ARRAY of IDs and, to use it only for particular id from list_users() which also returns ARRAY

I know I can use joined query, but that’s not the point at all, as I have lots of queries that I need to split

Answer 1

why arent you using a JOIN statement, and making two queries into one?

This will reduce db load, decrease query times, and also reduce clutter in your models.

SELECT p.post_id, p.post_title, p.post_content, u.user_id, u.username FROM posts p LEFT JOIN users u ON u.user_id = p.user_id

you can also do this using active records. Which will avoid having to use full blown queries, and more of a CI methodology to SQL.

http://codeigniter.com/user_guide/database/active_record.html

$this->db->select('p.post_id, p.post_title, p.post_content, u.user_id, u.username');
$this->db->from('posts p');
$this->db->join('users u', 'u.user_id = p.user_id');
$q = $this->db->get();

$q->result();

---

Edit:
You can return the value as an object.. IE: $this->user_id then reference it in the posts function. Ideally you should call the first function in your Controller, return $user_id and then reference that in your next function.. This is definitely not best case though, you should use JOINs as they are less taxing on the db.

//controller

function test(){
  $users = $this->exampleModel->list_users();
  //manipulate user data if needed
  $posts = $this->exampleModel->list_posts($users);
}