本来，对于空值的列，就有区分的功能。如果要自己做，参考

http://www.foxtable.com/bbs/dispbbs.asp?BoardID=2&ID=83243&skin=0

方法一：直接把空格替换掉

For Each dr As DataRow In DataTables("表A").datarows
    dr("第一列") = dr("第一列").replace(" ", "")
Next

方法二：编写代码处理筛选

Dim idx As String = "-1,"
Dim idx_temp As String = ""
Dim pdr As DataRow = Nothing
Dim count As Integer = 0
Dim cs As String = "第一列"
For Each dr As DataRow In DataTables("表A").Select("", cs)
    Dim flag As Boolean = False
    If pdr IsNot Nothing Then
        For Each c As String In cs.split(",")
            If pdr(c).replace(" ","") <> dr(c).replace(" ", "") Then
                flag = True
                Exit For
            End If
        Next
        If flag Then
            If count > 1 Then
                idx &= idx_temp
            End If
            count = 1
            idx_temp = ""
        Else
            count += 1
            idx_temp &= dr("_Identify") & ","
        End If
    Else
        count += 1
    End If
    pdr = dr
Next

If count > 1 Then
    idx &= idx_temp
End If

Tables("表A").filter = "_Identify not In (" & idx.trim(",") & ")"

 对表格进行排序，循环每一行，如果当前一行数据跟上一行数据不一样，就记录当前行的_Identify，最后得到的就是每种不同数据的第一行。

 或者这样这样理解， 对表格进行排序，循环每一行，如果当前一行数据跟上一行数据不一样，如果是第一行，就不记录，接下来的，全部记录，最后就得到全部多余重复的数据。