Overrides Drupal\views\Plugin\views\join\JoinPluginBase::buildJoin().
Overrides JoinPluginBase::buildJoin
public function buildJoin($select_query, $table, $view_query) {
// Add an additional hardcoded condition to the query.
$this->extra = 'views_test_data.uid = ' . $this
->getJoinValue();
parent::buildJoin($select_query, $table, $view_query);
}