VB.Net สินค้าที่ขายดีที่สุด 5 อันดับ มันไม่ยอม Sum อะคะ มันเลือกที่ยอดจำนวนสูงสุด ขอบคุณคะ

 SQLConnection.Close()
        SQLConnection.Open()


        Dim where As String = ""

        where = "and  b.status like '%" + TextBox1.Text + "%' group BY  amount DESC LIMIT 0,5 "



        Dim cryrpt As New cry_producttop

        SQLStatement = "select a.bill_id,a.ps_date,a.sum_price,a.emp_id,a.cus_id,a.status,b.pro_id,b.pro_name,b.amount,SUM(b.amount),b.pro_price,b.tax_sell,b.status  from product_sell a   left join  product_sell_detail b   on   a.bill_id = b.bill_id     where   a.ps_date between '" + Convert.ToDateTime(DateTimePicker1.Text).ToString("yyyy-MM-dd", New System.Globalization.CultureInfo("en-US")) + "' and '" + Convert.ToDateTime(DateTimePicker2.Text).ToString("yyyy-MM-dd", New System.Globalization.CultureInfo("en-US")) + "' " + where
       
        cmd = New MySqlCommand(SQLStatement, SQLConnection)
        Dim a As MySqlDataReader = cmd.ExecuteReader

        If a.HasRows Then
            dt = New DataTable
            dt.Load(a)


            cryrpt.SetDataSource(dt)
            CrystalReportViewer1.ReportSource = cryrpt
            cryrpt.SetParameterValue("date_from", DateTimePicker1.Text)
            cryrpt.SetParameterValue("date_to", DateTimePicker2.Text)
            Label3.Text = ""


        Else
            CrystalReportViewer1.ReportSource = Nothing
            MessageBox.Show("ไม่พบข้อมูล")
        End If

        CrystalReportViewer1.Refresh()

        SQLConnection.Close()
    End Sub