crm-summit/app/Models/ZonesModel.php

<?php namespace App\Models;

use CodeIgniter\Model;

class ZonesModel extends Model {

	protected $table 		= 'zones';
	protected $primaryKey 	= 'zoneid';
	protected $allowedFields = [ 'zonecode', 'zoneclass', 'parentzoneid', 'zonename' ];

	public function getAllProvinces() {
		$rows = $this->select('zoneid, zonename')->where('parentzoneid IS NULL', null, false)->findAll();
		return $rows;
	}

	public function getAllCities() {
		$rows = $this->select('zoneid, zonename')->where('parentzoneid IS NOT NULL', null, false)->findAll();
		return $rows;
	}

}