Provide the argument to use to link from the summary to the next level;
this will be called once per row of a summary, and used as part of
$view->getUrl().
Parameters
$data:
The query results for the row.
Overrides ArgumentPluginBase::summaryArgument
File
 
   - drupal/core/modules/views/lib/Drupal/views/Plugin/views/argument/ManyToOne.php, line 187
- Definition of Drupal\views\Plugin\views\argument\ManyToOne.
Class
  
  - ManyToOne 
- An argument handler for use in fields that have a many to one relationship
with the table(s) to the left. This adds a bunch of options that are
reasonably common with this type of relationship.
Definition terms:
Namespace
  Drupal\views\Plugin\views\argument
Code
public function summaryArgument($data) {
  $value = $data->{$this->base_alias};
  if (empty($value)) {
    $value = 0;
  }
  return $value;
}