C# 如何在EF父母中按子女的子女数排序？

我有团队编码人员项目组任务组

如何在实体框架中使用方法语法和代码优先方法（可能不加载子对象的子对象的整个集合内容，我只需要排序），根据任务数对团队进行有效排序

使EF生成此代码：

SELECT 
    [Project1].[ID] AS [ID], 
    [Project1].[Title] AS [Title]
    FROM ( SELECT 
        [Extent1].[ID] AS [ID], 
        [Extent1].[Title] AS [Title], 
        (SELECT 
            COUNT(1) AS [A1]
            FROM   [dbo].[NewBuildingObject] AS [Extent2]
            INNER JOIN [dbo].[NewBuildingHouse] AS [Extent3] ON [Extent2].[ID] = [Extent3].[ObjectID]
            INNER JOIN [dbo].[NewBuildingLayout] AS [Extent4] ON [Extent3].[ID] = [Extent4].[HouseID]
            WHERE [Extent1].[ID] = [Extent2].[BuilderID]) AS [C1]
        FROM [dbo].[Builder] AS [Extent1]
    )  AS [Project1]
    ORDER BY [Project1].[C1] ASC

SELECT 
    [Project1].[ID] AS [ID], 
    [Project1].[Title] AS [Title]
    FROM ( SELECT 
        [Extent1].[ID] AS [ID], 
        [Extent1].[Title] AS [Title], 
        (SELECT 
            COUNT(1) AS [A1]
            FROM  [dbo].[NewBuildingObject] AS [Extent2]
            INNER JOIN  (SELECT [Extent3].[ObjectID] AS [ObjectID]
                FROM  [dbo].[NewBuildingHouse] AS [Extent3]
                INNER JOIN [dbo].[NewBuildingLayout] AS [Extent4] ON [Extent3].[ID] = [Extent4].[HouseID] ) AS [Join1] ON [Extent2].[ID] = [Join1].[ObjectID]
            WHERE [Extent1].[ID] = [Extent2].[BuilderID]) AS [C1]
        FROM [dbo].[Builder] AS [Extent1]
    )  AS [Project1]
    ORDER BY [Project1].[C1] ASC

雅库布·马萨德的回答是：

context.Teams
.OrderBy(x => x.Coders
   .SelectMany(y => y.Projects)
   .SelectMany(y => y.Tasks)
   .Count());

var teams = context.Teams
    .OrderBy(team =>
        team.Coders.SelectMany(coder =>
            coder.Projects.SelectMany(project => project.Tasks)).Count());

制定此代码：

SELECT 
    [Project1].[ID] AS [ID], 
    [Project1].[Title] AS [Title]
    FROM ( SELECT 
        [Extent1].[ID] AS [ID], 
        [Extent1].[Title] AS [Title], 
        (SELECT 
            COUNT(1) AS [A1]
            FROM   [dbo].[NewBuildingObject] AS [Extent2]
            INNER JOIN [dbo].[NewBuildingHouse] AS [Extent3] ON [Extent2].[ID] = [Extent3].[ObjectID]
            INNER JOIN [dbo].[NewBuildingLayout] AS [Extent4] ON [Extent3].[ID] = [Extent4].[HouseID]
            WHERE [Extent1].[ID] = [Extent2].[BuilderID]) AS [C1]
        FROM [dbo].[Builder] AS [Extent1]
    )  AS [Project1]
    ORDER BY [Project1].[C1] ASC

SELECT 
    [Project1].[ID] AS [ID], 
    [Project1].[Title] AS [Title]
    FROM ( SELECT 
        [Extent1].[ID] AS [ID], 
        [Extent1].[Title] AS [Title], 
        (SELECT 
            COUNT(1) AS [A1]
            FROM  [dbo].[NewBuildingObject] AS [Extent2]
            INNER JOIN  (SELECT [Extent3].[ObjectID] AS [ObjectID]
                FROM  [dbo].[NewBuildingHouse] AS [Extent3]
                INNER JOIN [dbo].[NewBuildingLayout] AS [Extent4] ON [Extent3].[ID] = [Extent4].[HouseID] ) AS [Join1] ON [Extent2].[ID] = [Join1].[ObjectID]
            WHERE [Extent1].[ID] = [Extent2].[BuilderID]) AS [C1]
        FROM [dbo].[Builder] AS [Extent1]
    )  AS [Project1]
    ORDER BY [Project1].[C1] ASC

---

你可以试试类似的东西

context.Teams
.OrderBy(x => x.Coders
   .SelectMany(y => y.Projects)
   .SelectMany(y => y.Tasks)
   .Count());

---

您可以像这样使用

SelectMany

：

var teams = context.Teams
    .OrderBy(team =>
        team.Coders.SelectMany(coder =>
            coder.Projects.SelectMany(project => project.Tasks)).Count());

---

非常感谢。你的解决方案很有效。我认为这是最早的答案。