主题：[求助]集合

 简单的做法是，使用查询表联合两个表，然后获取。

Dim cmd As New SQLCommand
cmd.CommandText = "select a.第一列, a.第二列, a.第三列 from {表A}, {表B}"
Dim dt As DataTable = cmd.ExecuteReader
Dim ary As List(Of String()) = dt.GetUniqueValues("", "第一列", "第二列", "第三列")
msgbox(ary.count)

Dim Ary1s As List(Of String())  = DataTables("冷轧物流").GetUniqueValues("[熔铸编号] IS NOT NULL", "品种","合金","保税")
Dim Ary2s As List(Of String())  = DataTables("冷轧盘点表").GetUniqueValues("[熔铸编号] IS NOT NULL", "品种","合金","保税")
Dim Ary3s As List(Of String())  = DataTables("冷轧物流").GetUniqueValues("[熔铸编号] IS NOT NULL", "品种","合金","保税")

For Each Ary2 As String() In Ary2s
    For Each Ary1 As String() In Ary1s
        For i As Integer = 0 To Ary1.Length
            If Ary1(i) <> Ary2(i) Then
                Ary3s.Add(Ary2)
                Exit For
            End If
        Next
    Next
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