聚合具有相同值的两列或多列的行

Question

在 asp.net c# 中，我有一大组值。我正在尝试聚合具有相同值的行并对它们的一些值求和（objective 是在 table 中有一行与聚合信息）......有没有聚合行的方法有两个或多个具有相同值的列并对第三列求和？

Table 示例：

id      | column1 | column2  |column to sum
--------+---------+----------+-------------
1       | 3       | 1        |10
2       | 3       | 1        |10
3       | 3       | 2        |10
4       | 4       | 2        |10
5       | 4       | 2        |10
6       | 7       | 3        |10
7       | 7       | 3        |10
8       | 7       | 3        |10
9       | 5       | 1        |10
10      | 5       | 4        |10

Objective：具有相同 column1 和 column2 值的 "column to sum" 行的总和值

它会这样结束：

id      | column1 | column2  |column to sum
--------+---------+----------+-------------
-       | 3       | 1        |20
3       | 3       | 2        |10
-       | 4       | 2        |20
-       | 7       | 3        |30
9       | 5       | 1        |10
10      | 5       | 4        |10

有没有办法用 EF 或 LINQ 或 SQL STATEMENTS 来做到这一点？

谢谢

Answer 1

简单 GROUP BY 应该可以完成您的工作。如果你 select id 你会变得多余 columnToSum。

WITH CTE AS (
SELECT 1 as id, 3 as column1, 1 as column2,10 as [column to sum]
UNION
SELECT 2 as id, 3 as column1, 1 as column2,10 as [column to sum]
UNION
SELECT 3 as id, 3 as column1, 2 as column2,10 as [column to sum]
UNION
SELECT 4 as id, 4 as column1, 2 as column2,10 as [column to sum]
UNION
SELECT 5 as id, 4 as column1, 2 as column2,10 as [column to sum]
UNION
SELECT 6 as id, 7 as column1, 3 as column2,10 as [column to sum]
UNION
SELECT 7 as id, 7 as column1, 3 as column2,10 as [column to sum]
UNION
SELECT 8 as id, 7 as column1, 3 as column2,10 as [column to sum]
UNION
SELECT 9 as id, 5 as column1, 1 as column2,10 as [column to sum]
UNION
SELECT 10 as id, 5 as column1, 4 as column2,10 as [column to sum]
)

SELECT column1,column2,SUM([column to sum]) [column to sum] FROM CTE
GROUP BY column1,column2

Answer 2

在SQL,

SELECT column2, colum1, SUM(column to sum) GROUP BY column2, colum1

在 LINQ 查询语法中（未经测试，但应该如下所示）

           var result = from res in myTableOrClassList
                     group res by new { res.Column1, res.Column2 } into g
                     select new { column1 = g.Key.column1, colum2 = g.Key.column2, columnSum = g.Sum(f => f.columToSum) };

Linq 方法语法

    var linq = myTableOrClassList.GroupBy(p=> new { p.Column1, p.Column2 }).
                    Select(k=> new {column1 = k.Key.Column1, column2 = k.Key.Column2, sumColumn = k.Sum(each => each.columToSum) });

聚合具有相同值的两列或多列的行

Agregate rows with two or more columns with same value

linq

sql-server

entity-framework

linq-to-sql