Лесно:
SELECT
Val1,
Val2,
Val3,
(Val1 + Val2 + Val3) as 'Total'
FROM Emp
или ако искате само един ред:
SELECT
SUM(Val1) as 'Val1',
SUM(Val2) as 'Val2',
SUM(Val3) as 'Val3',
(SUM(Val1) + SUM(Val2) + SUM(Val3)) as 'Total'
FROM Emp