Codeigniter选择distinct并传递变量列表

Question

Just want to SELECT DISTINCT country FROM table WHERE user_id=$user_id, pass the country list from model to controller and then pass the JSON representation of the country list but as I am a newbie in Codeigniter I am not sure if wrote the query correctly and if I return the list or a single value. Could you please check my code.

Model:

public function did_get_country_list($user_id) {

        $this->db->distinct('country');
        $this->db->where('user_id',$user_id);
        $query = $this->db->get('table');

        if ($query->num_rows() >= 1) {
         foreach ($query->result() as $row)
        {
            $country = $row->country;
        }
        return $country;
        }
        else{
         return false;
        }       
    }   

Controller:

$country = $this->model_users->did_get_country_plans($user_id);

echo json_encode($country);

Answer 1

Your code looks almost ok to me, but I think you should change 2 lines:

1) Remove the check for num_rows before the actual query.

2) To return an array of countries, add [] at the end of $country to push the new values.

So, instead of this snippet:

    if ($query->num_rows() >= 1) {
     foreach ($query->result() as $row)
    {
        $country = $row->country;
    }
    return $country;
    }
    else{
     return false;
    }

You would have:

    $country = false;
    foreach ($query->result() as $row)
    {
        $country[] = $row->country;
    }
    return $country;