参考代码
Dim ls1 As List(Of String) = DataTables("表A").GetValues("第一列")Dim ls2 As List(Of String) = DataTables("表B").GetValues("第一列")For Each s As String In ls2 If ls1.Contains(s) = False Then ls1.add(s) End IfNext
msgbox(String.Join(",", ls1.ToArray))