如何在SQL Server 2005中查找表中多列的总和？

Question

我有一个Emp包含这些行的表:

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  |

我想找到SUM的Val1, Val2, Val3,并且将在显示Total列.

Answer 1

简单:

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

或者如果你只想要一行:

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

Answer 2

您还必须了解null记录:

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

用法ISNULL:

ISNULL(col_Name, replace value)

Answer 3

就像一个普通的SELECT？

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

或者您想确定总数并使用这些值更新表格？

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

如果你想让这个总数始终是当前的 - 你的表中应该有一个计算列:

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

然后,您将始终获得当前总数 - 即使值发生变化:

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

Answer 4

尝试这个：

select sum(num_tax_amount+num_total_amount) from table_name;