ถามเรื่องการวนลูป while หน่อยคับ คือ ต้องการรวมค่าใน DataBase จึงใช้คำสั่ง while แล้วโปรแกรมกลับ วน 4 รอบ

Dim StrConn As String
        Dim Sql As String
        StrConn = WebConfigurationManager.ConnectionStrings("conn").ConnectionString
        Dim Conn As New SqlConnection(StrConn)
        Conn.Open()
        Dim a, b, c, d, f, g, h, i As Integer
        Sql = "SELECT * FROM Dtac_sale  where month(Dtac_sale.date_now)= " & Month.Text & " AND year(Dtac_sale.date_now)= " & Year.Text & " "
        Dim sqlCom As New SqlCommand(Sql, Conn)
        Dim dr As SqlDataReader = sqlCom.ExecuteReader
        While dr.Read
            a = dr.Item("sale_60")
            b = dr.Item("sale_100")
            c = dr.Item("sale_200")
            d = dr.Item("sale_300")
            f = dr.Item("back_60")
            g = dr.Item("back_100")
            h = dr.Item("back_200")
            i = dr.Item("back_300")
            Response.Write(a)
            Response.Write("<br>")
            Session("z") = Session("z") + a
            Session("y") = Session("y") + b
            Session("x") = Session("x") + c
            Session("w") = Session("w") + d
            Session("v") = Session("v") + f
            Session("u") = Session("u") + g
            Session("t") = Session("t") + h
            Session("s") = Session("s") + i
        End While