Adds a condition.
string|ConditionAggregateInterface $field:
string $function:
mixed $value:
string $operator:
string $langcode:
\Drupal\Core\Entity\Query\ConditionAggregateInterface The called object.
\Drupal\Core\Entity\Query\QueryInterface::condition()
public function condition($field, $function = NULL, $value = NULL, $operator = NULL, $langcode = NULL);