使用LINQ获得连接表中的最大数量

Question

我经历了很多关于Stackoverflow的问题，恐怕我仍然无法找到答案。我正在使用实体框架。使用LINQ我试图在过去七天内找到最受欢迎的课程。我有参与查询，日程，会议，地点四个表和联接表ClientSesions

日程表的型号是

 public class Schedule{ 
     public Guid ScheduleID { get; set; } 
     public Guid CompanyID { get; set; } 
     public Guid LocationID { get; set; } 
     public Guid SessionID { get; set; } 
     public Guid SessionTypeID { get; set; } 
     public Guid ParentScheduleID { get; set; } 
     public int ClassDay { get; set; } 
     public int ClassMonth { get; set; } 
     public int ClassYear { get; set; } 
     public string Day { get; set; } 
     public DateTime StartTime { get; set; } 
     public DateTime EndTime { get; set; } 
     public DateTime ClassDate { get; set; }  
     public string Title { get; set; } 
     public string Description { get; set; } 
     public bool Deleted { get; set; } 
     public int SessionSize { get; set; }  
     public virtual Session Session { get; set; } 
     public virtual Company Company { get; set; } 
     public virtual Location Location { get; set; } 
     public virtual SessionType SessionType { get; set; } 
} 

会话模式

public class Session { 

    public System.Guid SessionID { get; set; } 
    public System.Guid ProgramID { get; set; } 
    public System.Guid CompanyID { get; set; } 
    public Nullable<Guid> SessionTypeID { get; set; } 
    public Int32 SessionSize { get; set; } 
    public bool Display { get; set; } 
    public virtual ClientSession ClientSession { get; set; } 
} 

的交界处的ClientSession表

public class ClientSession 
{ 
    public Guid ClientID { get; set; } 
    public Guid CompanyID { get; set; } 
    public Guid SessionID { get; set; } 
    public Nullable<System.Guid> TransactionID { get; set; }  
    // Navigation Properties 
    public virtual Client Client { get; set; } 
    public virtual Session Session { get; set; } 
} 

我写了下面的SQL代码按预期工作，但我担心我只是没有足够的知识或经验将其转换为Linq。

SELECT TOP 1 s.ClassDate, l.LocationName, COUNT(c.SessionID) as num_att 
FROM Schedules s 
JOIN Sessions ss ON s.SessionID = ss.SessionID 
JOIN Sessions ss ON s.SessionID = ss.SessionID 
JOIN ClientSessions c ON ss.SessionID = c.SessionID 
JOIN Locations l ON s.LocationID = l.LocationID 
WHERE s.CompanyID = '109' 
AND s.LocationID = '4' 
AND (s.ClassDate >= DATEADD(DAY, -7, GETDATE())) 
GROUP BY s.ClassDate, l.LocationName 
ORDER BY num_att DESC, s.ClassDate DESC 

这是据我设法得到

var details = _repositoryBase.AllIncluding<Schedule>(x => x.Session, x => x.Location) 
.Where(x => x.CompanyID == mostPopularSessionRequest.CompanyID 
&& x.LocationID == mostPopularSessionRequest.LocationID 
.GroupBy(x => x.ClassDate) 

任何帮助，在向我展示如何获得此完成了其余的将非常感激。

在此先感谢您提供任何帮助。

Answer 1

var query = from s in Schedules 
         join ss in Schedules on s.SessionID equals ss.SessionID 
         join c in ClientSessions on ss.SessionID equals c.SessionID 
         join l in Locations on s.LocationID equals l.LocationID 
         where s.CompanyID = 109 && s.LocationID = 4 && (s.ClassDate >= DateTime.Now.AddDays(-7)) 
         group c by new 
         { 
          c.ClassDate, 
          l.LocationName 
         } into gcs 
         select new 
         { 
          ClassDate = gcs.Key.ClassDate, 
          LocationName = gcs.Key.LocationName, 
          SessionIDCount = gcs.c.Count() 
         };