LINQ 多个联接与一个分组依据

本文关键字：一个 LINQ | 更新日期: 2023-09-27 18:35:02

在尝试了很多之后，我决定在这里发布一个问题。我的代码如下：

var query =
            //Customers
            from customer in context.Customers
            //Engineer 1
            join engineer1 in context.Employees on customer.PrimaryEngineer equals
            engineer1.EmployeeId into eng1 
            from engineer1 in eng1.DefaultIfEmpty()
            //Engineer Top
            join engineerTop in context.Employees on customer.TopEngineer equals 
            topEngineer.EmployeeId into top
            from engineerTop in top.DefaultIfEmpty()
然后，我

想要的我按三个表中的属性分组：客户，员工(每个工程师都重复此操作(

如何按三个表中的属性进行分组？

下一个代码： 

            group new {customer, engineer1, engineerTop} by new {customer.Name .....}

由于 engineer1 和 engineerTop 来自同一上下文而不起作用？

我对此感到非常困惑。

谢谢大家的帮助

LINQ 多个联接与一个分组依据

由于多个具有相同名称的属性，您可能需要为分组中的匿名类型属性分配一个名称。(是员工ID的两倍？

    var query = (
        //Customers
        from customer in context.Customers
        //Engineer 1
        join engineer1 in context.Employees on customer.PrimaryEngineer equals
        engineer1.EmployeeId into eng1 
        from engineer1 in eng1.DefaultIfEmpty()
        //Engineer Top
        join engineerTop in context.Employees on customer.TopEngineer equals 
        engineerTop.EmployeeId into top
        from engineerTop in top.DefaultIfEmpty()
        group new {customer, engineer1, engineerTop} by new {CustName = customer.Name, EmpId1 = engineer1.EmployeeId, EmpId2 = engineerTop.EmployeeId} into grp
        select new
        {
            Name = grp.Key.CustName,
            EmpId1 = grp.Key.EmpId1,
            EmpId2 = grp.Key.EmpId2
        });
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