将查询转换为linq [英] convert query to linq

问题描述

如何将此查询转换为linq



选择年份（CreatedAt），从会员计算（会员ID）

其中ID = 1

按年份分组（CreatedAt）

How to convert this query to linq

select year(CreatedAt),count(MemberID) from Members
where ID = 1
group by year(CreatedAt)

推荐答案

这真的不是那么难。努力奋斗。

我建议你下载 LinqPad [ ^ ]，您可以使用它来在线测试您的查询，并使用linq来解决任何问题。顺便说一下，它包含一组示例和教程 - 其中有几个可以帮助您解决此任务。

This is really not that hard. Struggle a little bit.
I suggest you download LinqPad[^], which you can use to test your queries online, and to play around with linq to anything. And by the way it contains a set of samples and tutorials - among which you will find several that will help you in solving this task.

我的建议是，如果你经常使用linq查询，

使用下面的链接并安装sql链接转换器，

即使我使用相同的..

http://www.linqpad.net/ [ ^ ]



它很简单，你可以在sql中构建任何复杂的查询然后在linqpad中复制粘贴然后在按钮单击中你会得到一个linq查询。

即使没有Linq的熟练知识，我已经完成了一个使用Linq的整个项目：





祝你好运..

Hi,
my advice is if you frequently using linq queries then,
use the below link and install sql to link converter,
even i use the same..
http://www.linqpad.net/[^]

it is so easy and you can just build any complex query in sql and then copy paste in linqpad then in a button click you will get a linq query.
even without having sound knowledge on Linq, i have completed a whole project which uses Linq :)


Good luck..

嗨dineshdena，



不要忘记

Hi dineshdena,

Don't forget

using System.Linq;

否则你ca不要使用LINQ扩展方法，你需要创建存储数据的类。

这是代码：

otherwise you can't use neither LINQ extension method and you need to create the class to store the data.
Here is the Code:

[DataContract]
   public class MemberModel
   {
       [DataMember]
       public string year{ get; set; }
       [DataMember]
       public string Count{ get; set; }
   }

var dataQuery =
    from Mem in Members
    where Mem.ID == 1
    group Mem by new { Mem.year(CreatedAt) } into g
    select new MemberModel()
    {
        year = g.Key.year(CreatedAt), 
        Count= g.Key.count(MemberID)
    };

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