Yii2 Select only few columns from related model - yii2

Question

In controller i have:
public function actionGetItems()
{
$model = new \app\models\WarehouseItems;
$items = $model->find()->with(['user'])->asArray()->all();
return $items;
}
In WarehouseItem model i have standard (created by gii) relation declaration:
public function getUser()
{
return $this->hasOne('\dektrium\user\models\User', ['user_id' => 'user_id']);
}
How can i control which column data do i get from "user" relation? I currently get all columns which is not good as that data is being sent to Angular in JSON format.
Right now i have to loop trough $items and filer out all columns i dont want to send.

Answer 1

You should simply modify the relation query like this :
$items = \app\models\WarehouseItems::find()->with([
'user' => function ($query) {
$query->select('id, col1, col2');
}
])->asArray()->all();
Read more : http://www.yiiframework.com/doc-2.0/yii-db-activequerytrait.html#with()-detail

Answer 2

Your code should go this way.
public function actionGetItems()
{
$items = \app\models\WarehouseItems::find()
->joinWith([
/*
*You need to use alias and then must select index key from parent table
*and foreign key from child table else your query will give an error as
*undefined index **relation_key**
*/
'user as u' => function($query){
$query->select(['u.user_id', 'u.col1', 'u.col2']);
}
])
->asArray()
->all();
return $items;
}

Answer 3

Inside WarehouseItem model
/**
* #return ActiveQuery
*/
public function getUser()
{
$query = User::find()
->select(['id', 'col1', 'col2'])
->where([
'id' => $this->user_id,
]);
/**
* Default hasOne, setup multiple for hasMany
* $query->multiple = true;
*/
return $query;
}