Есть GROUP_CONCAT, есть GROUP_SUM?

кол-во - это целое число. Этот SQL работает, но я хочу суммировать значения кол-во, а не объединять их. Нет GROUP_SUM: называется как-то еще?

SELECT sku as filterSKU, storenumber as storenumberSKU,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 0 THEN qty ELSE NULL END)) AS Monday,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 1 THEN qty ELSE NULL END)) AS Tuesday,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 2 THEN qty ELSE NULL END)) AS Wednesday,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 3 THEN qty ELSE NULL END)) AS Thursday,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 4 THEN qty ELSE NULL END)) AS Friday,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 5 THEN qty ELSE NULL END)) AS Saturday,
      GROUP_CONCAT((CASE weekdayoftransaction WHEN 6 THEN qty ELSE NULL END)) AS Sunday
    FROM `reconciled`.sale 
    GROUP BY sku, storenumber;

Вот таблица:

CREATE TABLE `sale` (
  `saleID` int(11) NOT NULL AUTO_INCREMENT,
  `EmployeeFirstName` varchar(45) DEFAULT NULL,
  `EmployeeLastName` varchar(45) DEFAULT NULL,
  `ProductDescription` varchar(45) DEFAULT NULL,
  `Unit` varchar(45) DEFAULT NULL,
  `SKU` varchar(45) DEFAULT NULL,
  `Qty` int(11) DEFAULT NULL,
  `UnitCost` decimal(10,3) DEFAULT NULL,
  `UnitPrice` decimal(10,3) DEFAULT NULL,
  `Manufacturer` varchar(45) DEFAULT NULL,
  `EmployeeNumber` varchar(45) DEFAULT NULL COMMENT 'The employee who handled the transaction',
  `LoyaltyNumber` varchar(45) DEFAULT NULL,
  `StoreNumber` varchar(45) DEFAULT NULL,
  `DateOfTransaction` date DEFAULT NULL,
  `TimeOfTransaction` time DEFAULT NULL,
  `DateOfTransactionString` varchar(45) DEFAULT NULL,
  `TimeOfTransactionString` varchar(45) DEFAULT NULL,
  `WeekdayOfTransaction` int(11) DEFAULT NULL,
  `MonthOfTransaction` int(11) DEFAULT NULL,
  `YearOfTransaction` int(11) DEFAULT NULL,
  `WeekdayNameOfTransaction` varchar(45) DEFAULT NULL,
  `MonthNameOfTransaction` varchar(45) DEFAULT NULL,
  `TotalPrice` decimal(10,3) DEFAULT NULL,
  PRIMARY KEY (`saleID`)
) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=utf8;