common/modules/product/models/ProductVariantListSearch.php

<?php
    
    namespace common\modules\product\models;
    
    use yii\base\Model;
    use yii\data\ActiveDataProvider;
    
    /**
     * ProductVariantSearch represents the model behind the search form about
     * `backend\models\ProductVariant`.
     */
    class ProductVariantListSearch extends ProductVariant
    {
        
        public function behaviors()
        {
            return [];
        }
        
        /**
         * @inheritdoc
         */
        public function rules()
        {
            return [
                [
                    [
                        'product_variant_id',
                        'product_id',
                        'product_unit_id',
                    ],
                    'integer',
                ],
                [
                    [
                        'sku',
                        'remote_id',
                    ],
                    'safe',
                ],
                [
                    [
                        'price',
                        'price_old',
                        'stock',
                    ],
                    'number',
                ],
            ];
        }
        
        /**
         * @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, $product_id = false)
        {
            $query = ProductVariant::find();
            
            // add conditions that should always apply here
            
            $dataProvider = new ActiveDataProvider([
                'query' => $query,
            ]);
            
            $this->load($params);
            
            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;
            }
            
            if($product_id) {
                $query->andFilterWhere([
                    'product_id' => $product_id,
                ]);
            }
            
            // grid filtering conditions
            $query->andFilterWhere([
                'product_variant_id' => $this->product_variant_id,
                'price'              => $this->price,
                'price_old'          => $this->price_old,
                'stock'              => $this->stock,
                'product_unit_id'    => $this->product_unit_id,
            ]);
            
            $query->andFilterWhere([
                    'like',
                    'sku',
                    $this->sku,
                ])
                  ->andFilterWhere([
                      'like',
                      'remote_id',
                      $this->remote_id,
                  ]);
            
            return $dataProvider;
        }
    }