1、参考

http://www.foxtable.com/bbs/dispbbs.asp?BoardID=2&ID=107764&skin=0

2、如果你只有日期列，没有月份列，你需要对1的代码进行微小修改，具体发实例上来测试。

比如代码

Dim idx As String = "-1,"
Dim idx_temp As String = ""
Dim pdr As DataRow = Nothing
Dim count As Integer = 0
Dim cs As String = "月份,工号"
Dim t As Table = Tables("员工收入合计2018")
For Each dr As DataRow In t.DataTable.Select("", cs)
   
    Dim flag As Boolean = False
    If pdr IsNot Nothing Then
        For Each c As String In cs.split(",")
            If pdr(c) <> dr(c) Then
                flag = True
                Exit For
            End If
        Next
    End If
    If flag Then
        If count > 1 Then
            idx &= idx_temp
        End If
        count = 1
        idx_temp = ""
        idx_temp &= dr("_Identify") & ","
    Else
        count += 1
        idx_temp &= dr("_Identify") & ","
    End If
   
    pdr = dr
Next

If count > 1 Then
    idx &= idx_temp
End If

t.filter = "_Identify in (" & idx.trim(",") & ")"

如果得到冗余值，参考 http://www.foxtable.com/bbs/dispbbs.asp?BoardID=2&ID=114307&skin=0