循环访问SqlDataReader的最快方法？

Question

我有一个select语句需要引入数据库中的所有labnumber。但是有大约3000条记录，我想知道是否有更快的方法来做到这一点？这是代码。

    Try
        Dim labnumber As SqlCommand

        If GenStoredProcs.Location = "CL" Then
            labnumber = New SqlCommand("SELECT * FROM MAT_SAMPLE_TRACKING " &
                    "WHERE LABNO IN " &
                    "(SELECT DISTINCT LABNO FROM MAT_MAIN_GLASS_BEADS " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_CYLINDER " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_SHRP_MAIN " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_PAINT_WATERBORNE " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_STOREROOM_BLEND  " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_STONEROOM_INFO  " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_PAINT_EPOXY " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_WINTER_COARSE_MAIN " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_WINTER_FINE_MAIN " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_FINE_AGGREGATE " &
                    "UNION SELECT DISTINCT LABNO FROM MAT_REBAR_INFO) " &
                    "ORDER BY LABNO DESC ", modData.MATDB_Connection)
        Else
            'Load Tests table, only labs that have tests
            labnumber = New SqlCommand("SELECT * FROM MAT_SAMPLE_TRACKING " &
                        "WHERE LABNO IN " &
                        "(SELECT DISTINCT LABNO FROM MAT_MAIN_ASPHALT " &
                        "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_CONCRETE " &
                        "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_BRICKS " &
                        "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_GLASS_BEADS " &
                        "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_RICE " &
                        "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_WET_WASH " &
                        "UNION SELECT DISTINCT LABNO FROM MAT_MAIN_PRECAST) " &
                        "ORDER BY LABNO DESC ", modData.MATDB_Connection)
        End If
        'removed from else condition above should not be needed
        '"UNION SELECT DISTINCT LABNO FROM MAT_SHRP_MAIN " & _
        '"UNION SELECT DISTINCT LABNO FROM MAT_PAINT_WATERBORNE) " & _
        Dim reader As SqlDataReader = labnumber.ExecuteReader()

        If reader.HasRows Then
            While reader.Read()
                If Not IsDBNull(reader("LABNO")) Then
                    cboLabNumber.Items.Add(reader("LABNO"))
                End If
            End While
        End If
        reader.Close()