yii\redis\ActiveQuery::sum PHP Метод

Returns the number of records.

public sum ( string $column, Connection $db = null ) : integer
$column	string	the column to sum up
$db	Connection	the database connection used to execute the query. If this parameter is not given, the `db` application component will be used.
Результат	integer	number of records

    public function sum($column, $db = null)
    {
        return $this->executeScript($db, 'Sum', $column);
    }

ActiveQuery