SELECT C.*, T.CustomTypeName
FROM CCustoms AS C 
INNER JOIN TCustomType AS T ON C.CustomTypeID = T.CustomTypeID
WHERE C.CustDate > '20050101'

        Dim ds As DataSet

        ' Первая таблица - из первой базы данных
        Dim cnnCust As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;" _
& "Data Source=Q:\tmcustom.mdb")
        Dim adpCust As OleDbDataAdapter = New OleDbDataAdapter()
        adpCust.TableMappings.Add("Table", "Order")
        cnnCust.Open()
        ' Игнорировать предварительные расчеты
        Dim cmdCust As OleDbCommand = New OleDbCommand("SELECT CustomID, Customer,CustNum," _
& "CustDate, CustomTypeID, ModeID, Operator, ChangePrice FROM CCustoms " _
& "where CustDate > #01/12/2006# AND ModeID <> 0", cnnCust)
        cmdCust.CommandType = CommandType.Text
        adpCust.SelectCommand = cmdCust
        ds = New DataSet("myResultDataSet")
        adpCust.Fill(ds)
        cnnCust.Close()


        ' Вторая таблица - из другой базы данных (справочник)
        Dim cnnGuid As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;" _
& "Data Source=Q:\tmguides.mdb")
        Dim adpGuid As OleDbDataAdapter = New OleDbDataAdapter()
        adpGuid.TableMappings.Add("Table", "OrderType")
        cnnGuid.Open()
        Dim cmdGuid As OleDbCommand = New OleDbCommand("SELECT * FROM TCustomTypes", cnnGuid)
        cmdGuid.CommandType = CommandType.Text
        adpGuid.SelectCommand = cmdGuid
        adpGuid.Fill(ds)
        cnnCuid.Close()

        ' Обеспечить связь
        Dim dr As DataRelation
        Dim dcChild As DataColumn
        Dim dcParent As DataColumn

        dcChild = ds.Tables("Order").Columns("CustomTypeID")
        dcParent = ds.Tables("OrderType").Columns("CustomTypeID")
        dr = New System.Data.DataRelation("ccustoms2types", dcParent, dcChild)
        ds.Relations.Add(dr)

        Dim myRow As DataRow
        Dim myParentRow As DataRow
        ' Получить результат - пробежаться по строчкам таблицы
        For Each myRow In ds.Tables("Order").Rows
            ' Получить строку в таблице-справочнике
            myParentRow = myRow.GetParentRow("ccustoms2types")
            ' Вместе с главной таблицей вывести значение поля из связанной
            Console.WriteLine(myRow("CustomID") _
                & vbTab & myRow("CustomTypeID") _
                & vbTab & myParentRow("CustomTypeName"))
        Next