Emp_cd | Val1  | Val2  | Val3  | Total
-------+-------+-------+-------+-------
 1     | 1.23  | 2.23  | 3.43  |
 2     | 23.03 | 12.23 | 2.92  |
 3     | 7.23  | 9.05  | 13.43 |
 4     | 03.21 | 78.23 | 9.43  |

SELECT
   Val1,
   Val2,
   Val3,
   (Val1 + Val2 + Val3) as 'Total'
FROM Emp

SELECT
   SUM(Val1) as 'Val1',
   SUM(Val2) as 'Val2',
   SUM(Val3) as 'Val3',
   (SUM(Val1) + SUM(Val2) + SUM(Val3)) as 'Total'
FROM Emp

SELECT  (ISNULL(Val1,0) + ISNULL(Val2,0) + ISNULL(Val3,0)) as 'Total'
FROM Emp

ISNULL(col_Name, replace value)

SELECT
   Val1, Val2, Val3,
   Total = Val1 + Val2 + Val3
FROM dbo.Emp

UPDATE dbo.Emp
SET Total = Val1 + Val2 + Val3

ALTER TABLE dbo.Emp
ADD CurrentTotal AS Val1 + Val2 + Val3 PERSISTED

SELECT
   Val1, Val2, Val3, CurrentTotal
FROM dbo.Emp

select emp_cd, val1, val2, val3,
(val1+val2+val3) as total
from emp;

insert into emp select emp_cd, val1, val2, val3,
(val1+val2+val3) as total
from emp;

update emp set total = val1+val2+val3;

SELECT Emp_cd, Val1, Val2, Val3, SUM(Val1 + Val2 + Val3) AS TOTAL
FROM Emp
GROUP BY Emp_cd, Val1, Val2, Val3

SELECT (COALESCE(SUM(val1),0) + COALESCE(SUM(val2), 0)
+ COALESCE(SUM(val3), 0) + COALESCE(SUM(val4), 0)) AS 'TOTAL'
FROM Emp