[英]How do I retrieve a sum of distinct values to list?
The SQL table and model supporting my application is very similar to what I have displayed below. 支持我的应用程序的SQL表和模型与我在下面显示的非常相似。
Id | CustomerName | FruitName | Charge
_____________________________________
1 | Bob | Banana | 3.00
2 | Jill | Apple | 2.00
3 | Bob | Apple | 3.00
4 | Marvin | Banana | 1.00
5 | Sam | Pear | 4.00
[Key]
public int Id {get; set;}
public string CustomerName { get; set; }
public string FruitName { get; set;}
public string Charge {get; set;}
What I would like to do is pull the distinct FruitName
and the Charge.Sum()
and display it ToList()
in my view. 我想要做的是拉出不同的
FruitName
和Charge.Sum()
并在我的视图中显示它ToList()
。 Here is what I have tried 这是我尝试过的
var fruitToList = (from f in db.fruit select f).ToList();
var test = fruitToList.GroupBy(x => x.FruitName).Sum(y => y.Charge).Select(z => z.First());
return View(test.ToList());
I know that the reason why it does not work is because Charge
needs to be something like decimal.Parse(y.Charge)
but I cannot figure out how to do it within the Sum()
function. 我知道它不起作用的原因是因为
Charge
需要像decimal.Parse(y.Charge)
但我无法弄清楚如何在Sum()
函数中做到这一点。 Should I be going about this a different way? 我应该采取不同的方式吗?
Weird that the charge is a string, but never the less, since the data is already in a list you can group by fruit name extract the charge as a decimal and sum the group 奇怪的是,收费是一个字符串,但从来没有那么少,因为数据已经在一个列表中,你可以按水果名称分组提取费用作为小数并对组进行求和
For example 例如
//...
var test = fruitToList
.GroupBy(_ => _.FruitName, _ => new { Charge = decimal.Parse(_.Charge) })
.Select(g => new Fruit {
FruitName = g.Key,
Charge = g.Sum(f => f.Charge).ToString()
});
//...
Which could also be simplified even more 这也可以进一步简化
var test = fruitToList
.GroupBy(_ => _.FruitName, _ => decimal.Parse(_.Charge))
.Select(g => new Fruit {
FruitName = g.Key,
Charge = g.Sum().ToString()
});
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