backend/models/SearchCatalog.php

<?php
namespace backend\models;
use Yii;
use yii\base\Model;
use yii\data\ActiveDataProvider;
use common\models\Catalog;
/**
 * SearchCatalog represents the model behind the search form about `common\models\Catalog`.
 */
class SearchCatalog extends Catalog
{  
    /**
     * для поиска
     * @var $title
     */
    var $title;
    /**
     * @inheritdoc
     */
    public function rules()
    {
        return [
            [['catalog_id', 'parent_id', 'status', 'sort'], 'integer'], 
            // + поиск по title
            [['title'], 'safe']
        ];
    }
    /**
     * @inheritdoc
     */
    public function scenarios()
    {
        // bypass scenarios() implementation in the parent class
        return Model::scenarios();
    }
    /**
     * Creates data provider instance with search query applied
     *
     * @param array $params
     *
     * @return ActiveDataProvider
     */
    public function search($params)
    {
        $query = Catalog::find();
        $dataProvider = new ActiveDataProvider([
            'query' => $query,
        ]);
        
        // + поиск по title
        $dataProvider->setSort([
            'attributes' => [
                'catalog_id',
                'title' => [
                    'asc' => ['title' => SORT_ASC],
                    'desc' => ['title' => SORT_DESC],
                    'label' => 'title',
                    'default' => SORT_ASC
                ]
            ]
        ]);
        $this->load($params);
         
        // + поиск по title
        $query->joinWith(['relationCatalogLangPlus']);
        if (!$this->validate()) 
        {
            // uncomment the following line if you do not want to return any records when validation fails
            // $query->where('0=1');
 
            return $dataProvider;
        }
        $query->andFilterWhere([
            'catalog_id' => $this->catalog_id,
            'parent_id' => $this->parent_id,
            'status' => $this->status,
            'sort' => $this->sort,
        ]);
        $query->andFilterWhere(['like', 'cover', $this->cover]); 
        
        // + поиск по title
        if (! empty ($this->title))
        {
            $query->joinWith(['relationCatalogLangPlus' => function ($q) 
            {
                $q->where(['like', 'catalog_i18n.title', $this->title]);
            }]);
        }
        return $dataProvider;
    }
}