присоединение к 3 столу и возвращение

Question

У меня есть 3 таблицы, которые представляют собой расписание, расписание и место для консультаций, и я хочу объединить их так, чтобы все данные можно было легко найти

Расписание имеет

1. TimetableID
2. Lecture ID
3. ClassVenue
4. ClassStartTime
5. ClassEndTime

Расписание

1. ScheduleID
2. LectureID
3. ScheduleVenue
4. ScheduleStartTime
5. ScheduleEndTime

Слот для консультаций

1. ConsultationID
2. LectureID
3. StudentID
4. ScheduleID
5. remark

Вот мой код в метаданных

Partial Public Class CombinationOfTSC
    <Key()> _
    Public Property LectureID() As String
        Get
            Return m_LectureID
        End Get
        Set(value As String)
            m_LectureID = value
        End Set
    End Property
    Private m_LectureID As String

    Public Property StudentID() As String
        Get
            Return m_StudentID
        End Get
        Set(value As String)
            m_StudentID = value
        End Set
    End Property
    Private m_StudentID As String

    Public Property ttID() As String
        Get
            Return m_ttID
        End Get
        Set(value As String)
            m_ttID = value
        End Set
    End Property
    Private m_ttID As String

    Public Property ttClassVenue() As String
        Get
            Return m_ttClassVenue
        End Get
        Set(value As String)
            m_ttClassVenue = value
        End Set
    End Property
    Private m_ttClassVenue As String

    Public Property ttClassStartTime() As DateTime
        Get
            Return m_ttClassStartTime
        End Get
        Set(value As DateTime)
            m_ttClassStartTime = value
        End Set
    End Property
    Private m_ttClassStartTime As DateTime

    Public Property ttClassEndTime() As DateTime
        Get
            Return m_ttClassEndTime
        End Get
        Set(value As DateTime)
            m_ttClassEndTime = value
        End Set
    End Property
    Private m_ttClassEndTime As DateTime

    Public Property scID() As String
        Get
            Return m_scID
        End Get
        Set(value As String)
            m_scID = value
        End Set
    End Property
    Private m_scID As String

    Public Property scVenue() As String
        Get
            Return m_scVenue
        End Get
        Set(value As String)
            m_scVenue = value
        End Set
    End Property
    Private m_scVenue As String

    Public Property scStartTime() As DateTime
        Get
            Return m_scStartTime
        End Get
        Set(value As DateTime)
            m_scStartTime = value
        End Set
    End Property
    Private m_scStartTime As DateTime

    Public Property scEndTime() As DateTime
        Get
            Return m_scEndTime
        End Get
        Set(value As DateTime)
            m_scEndTime = value
        End Set
    End Property
    Private m_scEndTime As DateTime

    Public Property cID() As String
        Get
            Return m_cID
        End Get
        Set(value As String)
            m_cID = value
        End Set
    End Property
    Private m_cID As String

    Public Property cRemark() As String
        Get
            Return m_cRemark
        End Get
        Set(value As String)
            m_cRemark = value
        End Set
    End Property
    Private m_cRemark As String
End Class

В моем доменном классе код будет

Public Function GetCoTSC(lectureID As String) As IQueryable(Of CombinationOfTSC)
        Dim CSC As IQueryable(Of CombinationOfTSC) = From c In ObjectContext.ConsultationSlots Join s In ObjectContext.Schedules On c.ScheduleID Equals s.ScheduleID Join t In ObjectContext.TimeTables On t.LectureID Equals s.LectureID Where c.LectureID = s.LectureID = t.LectureID Select New CombinationOfTSC() With { _
                      .cID = c.ConsultationID, _
            .cRemark = c.Remark, _
            .StudentID = c.StudentID, _
             .LectureID = s.LectureID, _
            .scStartTime = s.ScheduleStartTime, _
            .scEndTime = s.ScheduleEndTime, _
            .scID = s.ScheduleID, _
            .scVenue = s.ScheduleVenue, _
              .ttID = t.TimeTableID, _
              .ttClassVenue = t.ClassVenue, _
              .ttClassStartTime = t.ClassStartTime, _
            .ttClassEndTime = t.ClassEndTime}
        Return CSC
    End Function

У меня ошибка на c.LectureID = s.LectureID = t.LectureID Я хочу получить комбинацию из 3 таблиц через lectureID, поскольку на 3 таблицах есть идентификатор лекции.Кто-нибудь помогает пожалуйста.

Answer 1

попробуй Where c.LectureID = s.LectureID and s.LectureID = t.LectureID вместо Where c.LectureID = s.LectureID = t.LectureID

Answer 2

Я не верю, что у вас может быть x = y = z.Вы пытались разделить их на пары?