Setting unknown property when trying to join table

Question

I've successfully joined a table to the elements table, however I can't can't seem to add a property so I can use it?

Getting the error Setting unknown property when trying to join table

Entry::find()
    ->addSelect(['craft_event_instances.instance_datetime'])
    ->leftJoin('craft_event_instances', '`craft_event_instances`.`entryId` = `elements`.`id`')

Thanks

Answer 1

You can't set a property of an element in Craft that does not exists in the field layout, as a behavior or as a public/private attribute in the object. Craft/Yii2 will throw an exception because the property instance_datetime probably does not exist.

In order to attach a custom value you have to either create a new element or you have to store this information somewhere else.

Edit

You could the following as well to fetch your values and store them into a new array

$query = Entry::find();
$columns = $query
    ->addSelect('craft_event_instances.instance_datetime')
    ->innerJoin('craft_event_instances', 'craft_event_instances.entryId = elements.id')
    ->createCommand()
    ->queryAll();
$yourCustomValues = [];
foreach($columns as $key => $column){
    $yourCustomValues[$column['id']] = $column['instance_datetime'];
    unset($columns[$key]['instance_datetime']);
}
$elements = $query->populate($columns);