主题：这里的第二组代码究竟出错在哪？

第一组代码

Dim bjs As List(Of String) = DataTables("九年级全年级").GetUniqueValues("[班别] Is Not NULL","班别")
Dim Count As Integer
Dim ColNames() As String = {"语","数","英","物","化","政","历","总分"}
Dim TotalName As String
For Each ColName As string In ColNames '
    For i As Integer = 0 To bjs.Count -1
        Dim drs As List(Of DataRow) = DataTables("九年级全年级").Select("[班别] = " & bjs(i), ColName & " DESC")
        Count = 0
        TotalName = ColName & "序"
        For n As Integer = 0 To drs.Count - 1
            Count = Count + 1
            If n > 0 AndAlso drs(n)(ColName ) = drs(n-1)(ColName) Then
                drs(n)(TotalName ) = drs(n-1)(TotalName )
            Else
                drs(n)(TotalName ) = Count
            End If
        Next
    Next
Next
Tables("九年级全年级").Sort = "总分 DESC"

第二组代码

Dim bjs As List(Of String) = DataTables("九年级全年级").GetUniqueValues("[学校] Is Not NULL","学校")
Dim Count As Integer
Dim ColNames() As String = {"语","数","英","物","化","政","历","总分"}
Dim TotalName As String
For Each ColName As string In ColNames '
    For i As Integer = 0 To bjs.Count -1
        Dim drs As List(Of DataRow) = DataTables("九年级全年级").Select("[学校] = " & bjs(i), ColName & " DESC")
        Count = 0
        TotalName = ColName & "序"
        For n As Integer = 0 To drs.Count - 1
            Count = Count + 1
            If n > 0 AndAlso drs(n)(ColName ) = drs(n-1)(ColName) Then
                drs(n)(TotalName ) = drs(n-1)(TotalName )
            Else
                drs(n)(TotalName ) = Count
            End If
        Next
    Next
Next
Tables("九年级全年级").Sort = "总分 DESC"

 文件如下图所示

此主题相关图片如下：01.jpg

在这样的文件中运行第一组代码，能正确排序，按班级排

我想要按学校排序，就将第一组代码换成第二组代码，运行时出错，（如下图所示）

此主题相关图片如下：02.jpg

不知道何原因，如果要按学校排，第二组代码应该怎么修改呢？请朋友们帮看看，谢谢。