如何在SQL Server中使用Group by對多列進行求和？

Question

我有一張名爲tblEmployee的表格。我想總結價值並按UserId分組。

tblEmployee：

+--------+----------+-------+ 
| UserId | UserName | Value | 
+--------+----------+-------+ 
|  1 | A  | 100 | 
|  1 | B  | 200 | 
|  1 | C  | 300 | 
|  2 | D  | 100 | 
|  3 | E  | 200 | 
|  3 | F  | 300 | 
+--------+----------+-------+ 

我想總結基於userid並顯示像下面輸出的值。

輸出：

+--------+----------+-------+---------+ 
    | UserId | UserName | Value | Result | 
    +--------+----------+-------+---------+ 
    |  1 | A  | 100 |   | 
    |  1 | B  | 200 | 600 | 
    |  1 | C  | 300 |   | 
    |  2 | D  | 100 | 100 | 
    |  3 | E  | 200 |   | 
    |  3 | F  | 300 | 500 | 
    +--------+----------+-------+---------+ 

怎麼辦呢？

Answer 1

select 
userid,username, 
value, 
sum(value) over (partition by userid) as totalval 
from table 

Answer 2

如果你不想使用的分區，你還可以使用子查詢與GROUP BY得到你想要的輸出：

SELECT t1.UserId, t1.UserName, t1.Value, t2.Result 
FROM tblEmployee t1 
INNER JOIN 
(
    SELECT UserId, SUM(Value) AS Result 
    FROM tblEmployee 
    GROUP BY UserId 
) t2 
ON t1.UserId = t2.UserId