Yii2：下拉列表

I'm trying to create A Point of sale in YII2 so i need to create a select2 for items search in sales page , i need it to search between to tables items , Bar_code i made it in tow tables because there is items have more than 1 Bar_code

I know how the select2 works and its works with me fine in on table

<?= $form->field($model, 'item_id')->widget(select2::className(),[
   'data'=>  arrayhelper::map(items::find()->all(),'item_id','item_name'),
   'options'=>['placeholder'=>'Enter item name or scan barcode'],
   'pluginOptions'=>[
     'allowClear'=>true  
   ],
])?>`

but in tow its complicated or is there other way to do it ?

try this

<?php
    $data1 = arrayhelper::map(Items::find()->all(),'item_id','item_name'),
    $data2 = arrayhelper::map(Items2::find()->all(),'item_id','item_name'),
?>

<?= $form->field($model, 'item_id')->widget(select2::className(),[
   'data'=>  ["$data1", "$data2"],
   'options'=>['placeholder'=>'Enter item name or scan barcode'],
   'pluginOptions'=>[
     'allowClear'=>true  
   ],
])?>`