php use yii db Migration Handles the creation of table list Has foreig

<?php

use yii\db\Migration;

/**
 * Handles the creation of table `list`.
 * Has foreign keys to the tables:
 *
 * - `list`
 */
class m190325_203905_create_list_table extends Migration
{
    /**
     * {@inheritdoc}
     */
    public function safeUp()
    {
        $this->createTable('list', [
            'id' => $this->primaryKey(),
            'title' => $this->string(),
            'parent_id' => $this->integer(),
        ]);

        // creates index for column `parent_id`
        $this->createIndex(
            'idx-list-parent_id',
            'list',
            'parent_id'
        );

        // add foreign key for table `list`
        $this->addForeignKey(
            'fk-list-parent_id',
            'list',
            'parent_id',
            'list',
            'id',
            'CASCADE'
        );
    }

    /**
     * {@inheritdoc}
     */
    public function safeDown()
    {
        // drops foreign key for table `list`
        $this->dropForeignKey(
            'fk-list-parent_id',
            'list'
        );

        // drops index for column `parent_id`
        $this->dropIndex(
            'idx-list-parent_id',
            'list'
        );

        $this->dropTable('list');
    }
}



<?php
/**
 * Created with love by АльянсЭкспресс.
 * Author: Anochin Nikolay
 * Email: titan12345@mail.ru
 * Phone: +7 925 174 1314
 * Date: 25.03.2019
 * Time: 23:43
 */


namespace console\controllers;


use yii\console\Controller;
use yii\helpers\ArrayHelper;

/**
 * Class TestController
 * @package console\controllers
 */
class TestController extends Controller
{
    private function setListFixtures() {
        $sql = "
            insert into list (title, parent_id) VALUES 
            ('a', null), ('e', 4), ('d', 3), ('b', 1), ('c', 2) 
        ";

        \Yii::$app->db->createCommand($sql)->execute();
    }

    private function echoList($list) {
        print_r($list);
        var_dump(implode(',', ArrayHelper::getColumn($list, 'title')) . "\n");
    }

    private function insertBetween($position = 4) {
        $sql = "
            insert into list (title, parent_id) VALUES 
            ('f', :pos)
        ";

        \Yii::$app->db->createCommand($sql, [':pos' => $position])->execute();
        $id = \Yii::$app->db->getLastInsertID();

        // Вставим между d и e букву f
        $sql = '
            update list set parent_id = :id where parent_id = :pos and id != :id
        ';
        \Yii::$app->db->createCommand($sql, [':id' => $id, ':pos' => $position])->execute();
    }

    public function actionList() {
//        $this->setListFixtures();

        $sql = '
            select list.* from list
            left join list child_list on list.id = child_list.id
            order by (CASE WHEN list.parent_id IS NULL THEN 0 ELSE 1 END), list.parent_id
        ';

        $res = \Yii::$app->db->createCommand($sql)->queryAll();
//        $this->echoList($res);
//        $this->insertBetween();
//        $res = \Yii::$app->db->createCommand($sql)->queryAll();
        $this->echoList($res);
    }
}