SELECT ROUND(SUM(paramsObject.Qot),1) as Qot,
ROUND(SUM(paramsObject.Qgvs),1) as Qgvs,
ROUND(SUM(Qot + Qgvs)) as total // <--- Как реализовать данное вычисление
FROM paramsObject
LEFT JOIN objectsSource ON objectsSource.id = paramsObject.idObject
WHERE objectsSource.parentTo = 98;