我有一个LINQ问题。假设我有一个包含以下值的数据库:
===================
Date,product,orders
-------------------
1/2/2003,apple,3
1/2/2003,orange,5
1/3/2003,orange,6
1/4/2003,grape,2
===================
如何使用LINQ获取按日期对项目进行分组的结果,并将它们放入如下所示的变量中:
==========================
Date, Apple, Orange, Grape
--------------------------
1/2/2003,3,5,0
1/3/2003,0,6,0
1/3/2003,0 0,2
==========================
非常感谢任何帮助。谢谢!
答案 0 :(得分:4)
这是我做的测试:
var data = new []{
new { Date = new DateTime(2003, 1, 2), Product = "apple", Orders = (int?) 3 },
new { Date = new DateTime(2003, 1, 3),Product = "orange", Orders = (int?) 5 },
new { Date = new DateTime(2003, 1, 4), Product = "grape", Orders = (int?) 2 },
new { Date = new DateTime(2003, 1, 4), Product = "grape", Orders = (int?) null }
};
var result = data.GroupBy(x => x.Date)
.Select(g => new {
Date = g.Key,
Apples = g.Where(x => x.Product == "apple").Sum(x => x.Orders),
Oranges = g.Where(x => x.Product == "orange").Sum(x => x.Orders),
Grapes = g.Where(x => x.Product == "grape").Sum(x => x.Orders)
});
测试数据的结果不包含空值,但苹果,橘子和葡萄的结果为0。
答案 1 :(得分:0)
使用Linq to SQL,你可以做类似的事情;
var query = from p in products order by p.Date select p;
我不确定你的意思是“把它们变成变量”。
答案 2 :(得分:0)
试试这个:
var x = from tb in mytable
group date by tb.date;