使用VB.NET在VS2019中Linq到SQL-外部左连接？

我正在努力从linq到SQL查询中获得所需的结果。我可以找到所有person表记录，或者只找到具有相应date_表条目的记录。这是我正在使用的查询，结果只返回MK编号101和104。我想是因为他们今天没有有效的记录而错过了100号和105号吧

其中Person\u data\u table.MK=Date\u table.FK和Date\u table.Allocated“休假”和Date\u table.Allocated“生病”和Date\u table.Date=Today和Person\u data\u table.Team=“A”

这是表格数据（注意今天是20年3月15日）-请将答案保存在VB中，因为C#答案在我翻译后不会起作用谢谢你的帮助

问候

彼得

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请注意，您也在此处发布了您的问题。 你的问题还没有解决吗？您可以按如下方式尝试我的代码。很抱歉，我没有使用SQL，我使用了类，但这并不影响结果

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim MK100 As NewPerson = New NewPerson With {
            .MK = "100",
            .First_Name = "Mike",
            .Last_Name = "Smith",
            .Team = "A"
        }
        Dim MK101 As NewPerson = New NewPerson With {
            .MK = "101",
            .First_Name = "Dave",
            .Last_Name = "Sharp",
            .Team = "A"
        }
        Dim MK102 As NewPerson = New NewPerson With {
            .MK = "102",
            .First_Name = "Roger",
            .Last_Name = "Hands",
            .Team = "A"
        }
        Dim MK103 As NewPerson = New NewPerson With {
            .MK = "103",
            .First_Name = "Keely",
            .Last_Name = "Riller",
            .Team = "A"
        }
        Dim MK104 As NewPerson = New NewPerson With {
            .MK = "104",
            .First_Name = "Simon",
            .Last_Name = "Says",
            .Team = "A"
        }
        Dim MK105 As NewPerson = New NewPerson With {
            .MK = "105",
            .First_Name = "Eugene",
            .Last_Name = "Phillips",
            .Team = "A"
        }
        Dim MK106 As NewPerson = New NewPerson With {
            .MK = "106",
            .First_Name = "William",
            .Last_Name = "Nobody",
            .Team = "B"
        }
        Dim FK101 As NewDate = New NewDate With {
            .FK = "101",
            .Date_ = "15-Mar-20",
            .Allocated = "Job Number 1"
        }
        Dim FK102 As NewDate = New NewDate With {
            .FK = "102",
            .Date_ = "15-Mar-20",
            .Allocated = "Vacation"
        }
        Dim FK103 As NewDate = New NewDate With {
            .FK = "103",
            .Date_ = "15-Mar-20",
            .Allocated = "Sick"
        }
        Dim FK104 As NewDate = New NewDate With {
            .FK = "104",
            .Date_ = "15-Mar-20",
            .Allocated = "Job nunber 2"
        }
        Dim Person_Data_table As List(Of NewPerson) = New List(Of NewPerson) From {
            MK100,
            MK101,
            MK102,
            MK103,
            MK104,
            MK105,
            MK106
        }
        Dim Date_Table As List(Of NewDate) = New List(Of NewDate) From {
            FK101,
            FK102,
            FK103,
            FK104
        }
        Dim query = From NewPerson In Person_Data_table Group Join NewDate In Date_Table On NewPerson.MK Equals NewDate.FK Into gj = Group From subperson In gj.DefaultIfEmpty() Where (NewPerson.Team = "A") AndAlso (subperson Is Nothing OrElse ((subperson.Allocated <> "Vacation") AndAlso (subperson.Allocated <> "Sick"))) Select New With {NewPerson.MK, NewPerson.First_Name, NewPerson.Last_Name, NewPerson.Team
        }

        For Each v In query
            ListBox1.Items.Add($"{v.MK,-15}{v.First_Name,-15}{v.Last_Name,-15}{v.Team}")
        Next
    End Sub
End Class

Class NewPerson
    Public Property MK As String
    Public Property First_Name As String
    Public Property Last_Name As String
    Public Property Team As String
End Class

Class NewDate
    Public Property FK As String
    Public Property Date_ As String
    Public Property Allocated As String
End Class

公共类表单1
私有子表单1_Load（发送方作为对象，e作为事件参数）处理MyBase.Load
Dim MK100作为新人=新新人{
.MK=“100”，
.First_Name=“Mike”，
.Last_Name=“Smith”，
.Team=“A”
}
Dim MK101作为新人=新新人{
.MK=“101”，
.First_Name=“Dave”，
.Last_Name=“Sharp”，
.Team=“A”
}
Dim MK102作为新人=新新人{
.MK=“102”，
.First_Name=“罗杰”，
.Last_Name=“Hands”，
.Team=“A”
}
Dim MK103作为新人=新新人{
.MK=“103”，
.First_Name=“Keely”，
.Last_Name=“Riller”，
.Team=“A”
}
Dim MK104作为新人=新新人{
.MK=“104”，
.First_Name=“Simon”，
.Last_Name=“说”，
.Team=“A”
}
尺寸MK105为新人=新新人{
.MK=“105”，
.First_Name=“Eugene”，
.Last_Name=“Phillips”，
.Team=“A”
}
尺寸MK106为新人=新新人{
.MK=“106”，
.First_Name=“William”，
.Last_Name=“无人”，
.Team=“B”
}
Dim FK101 As NewDate=带有{
.FK=“101”，
.Date=“20年3月15日”，
.Allocated=“作业编号1”
}
Dim FK102 As NewDate=带有{
.FK=“102”，
.Date=“20年3月15日”，
.Allocated=“假期”
}
Dim FK103 As NewDate=带有{
.FK=“103”，
.Date=“20年3月15日”，
.Allocated=“生病”
}
Dim FK104 As NewDate=带有{
.FK=“104”，
.Date=“20年3月15日”，
.Allocated=“作业编号2”
}
Dim Person_Data_表格作为列表（新人员）=来自的新列表（新人员）{
MK100，
MK101，
MK102，
MK103，
MK104，
MK105，
MK106
}
Dim Date_表作为列表（属于NewDate）=新列表（属于NewDate）来自{
FK101，
FK102，
FK103，
FK104
}
Dim query=From NewPerson In Person_Data_table Group将NewPerson.MK上的Date_table中的NewDate等于NewDate.FK加入gj=Group From gj.DefaultIfEmpty（）中的subperson，其中（NewPerson.Team=“A”）和also（subperson为Nothing或lse（（subperson.Allocated“Vacation”）和（subperson.Allocated“Sick”））选择New With{NewPerson.MK，NewPerson.First_Name，NewPerson.Last_Name，NewPerson.Team
}
对于查询中的每个v
ListBox1.Items.Add（$“{v.MK，-15}{v.First_Name，-15}{v.Last_Name，-15}{v.Team}”）
下一个
端接头
末级
类新人
公共属性MK作为字符串
公共属性名为字符串
公共属性姓氏为字符串
公共财产小组作为字符串
末级
类NewDate
公共属性FK作为字符串
公共属性日期作为字符串
作为字符串分配的公共属性
末级

其效果如下：