遇到个问题，一个月有多次清点记录，但是在统计分析的时候，只每个月只选择一次做为分析的对象，例如

想求每个月最后一次盘点与上个月最后一次盘点的变化率，得出的结果，请问这个筛选条件怎么写？

1、先筛选重复，如

Dim idx As String = "-1,"
Dim idx_temp As String = ""
Dim pdr As DataRow = Nothing
Dim count As Integer = 0
Dim cs As String = "日期"
For Each dr As DataRow In DataTables("表A").Select("", cs & " desc")
   
    Dim flag As Boolean = False
    If pdr IsNot Nothing Then
        If format(pdr("日期"), "yyyyMM") <> format(dr("日期"), "yyyyMM") Then
            flag = True
        End If
    End If
    If flag OrElse pdr Is Nothing Then
        If count > 1 Then
            idx &= idx_temp
        End If
        count = 1
        idx_temp = ""
    Else
        count += 1
        idx_temp &= dr("_Identify") & ","
    End If
   
    pdr = dr
Next

If count > 1 Then
    idx &= idx_temp
End If

Tables("表A").filter = "_Identify not in (" & idx.trim(",") & ")"  \'显示唯一值