c# - 在linq中求和并将多列分组为一个值

我有字段表：

ID,sales1, sales2, sales3
1   25      15       15
1   10      7        3
2   8       11       9
3   10      5        7
3   22      9        4

我需要按ID过滤表格，并返回sales1 + sales2 + sales3的总和。在MySQL中，这将与

SELECT (SUM(sales1) + SUM(sales2) + SUM(sales3)) AS total
WHERE id = 1
GROUP BY id

但是我无法在linq中使用它。
有人可以帮我弄这个吗？

最佳答案

在LinqPad中划在一起：

void Main()
{
    //since I don't have a suitable database at hand
    //I'm emulating with a list
    var sales = new List<Sale>()
    {
        new Sale() {Id = 1, Sales1 = 25, Sales2= 15, Sales3= 15},
        new Sale() {Id = 1, Sales1 = 10, Sales2= 7, Sales3= 3},
        new Sale() {Id = 2, Sales1 = 8, Sales2= 11, Sales3= 9},
        new Sale() {Id = 3, Sales1 = 10, Sales2= 5, Sales3= 7},
        new Sale() {Id = 3, Sales1 = 22, Sales2= 9, Sales3= 4},
    };

    var filteredSales = sales.GroupBy (s => s.Id)//Need to Group to be able to use .Sum()
                             //.Where (s => s.Key == 1)
                             .Select (s => new
                              {
                               Id = s.Key,
                               Sum = s.Sum (x => x.Sales1 + x.Sales2 + x.Sales3)
                              }).Dump(); //ignore Dump. Only available in LinqPad
}

class Sale
{
    public int Id { get; set; }
    public int Sales1 { get; set; }
    public int Sales2 { get; set; }
    public int Sales3 { get; set; }
}

结果：

Id | Sum
1    75
2    28
3    57

取消注释where子句以按id进行过滤。
亲切的问候

关于c# - 在linq中求和并将多列分组为一个值，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/22582017/