คำสั่ง SQL ที่พอupdateข้อมูลในเเถว เเล้วถ้ามันซ้ำกับในช่วงจำนวนที่มีอยู่ ก็ไม่ให้ update

declare @min decimal(10,2) = 800
declare @max decimal(10,2) = 5000




UPDATE  promotion
SET     min_price = '800' , max_price = '1000' ,discount = '10'
WHERE  product ='X3753'
(select product,min_price ,max_price,discount
FROM promotion 
where product = 'X3753'
and (
		
		(@min >= min_price and @min <= isnull(max_price,99999999)) or
		(@max >= min_price and @max <= isnull(max_price,99999999))
	)

)

Public Function InsertProduct(ByVal Productid As Integer, CapMin As Decimal, CapMax As Decimal, CapDiscount As Decimal) As Boolean

        Dim reader2 As OleDbDataReader
        Dim comm2 As String
        comm2 = " UPDATE promotion"
        comm2 += " SET min_price = '" & CapMin & "' , max_price = '" & CapMax & "', discount = '" & CapDiscount & "' "
        comm2 += " where promotion_id = '" & Productid & "' "
        comm2 += " ( select product ,min_price,max_price,discount  "
        comm2 += " FROM promotion "
        comm2 += " where promotion_id = '" & Productid & "' "
        comm2 += " and (( '" & CapMin & "'  >= min_price and '" & CapMin & "' <= isnull(max_price,99999999)) "
        comm2 += " or ('" & CapMax & "' >= min_price and '" & CapMax & "' <= isnull(max_price,99999999)))) "

        Dim OleComm2 As New OleDbCommand(comm2, sqlconn)
        sqlconn.Open()
        reader2 = OleComm2.ExecuteReader(CommandBehavior.CloseConnection)
        If reader2.HasRows Then
            Return False
        Else
            Return True
        End If
    End Function

 Private Sub GridView_promotion_RowUpdating(sender As Object, e As GridViewUpdateEventArgs) Handles GridView_promotion.RowUpdating

        '   Dim cap_product_code As String = CType(GridView_promotion.Rows(e.RowIndex).Cells(3).Controls(0), TextBox).Text
        Dim cap_product_id As String = GridView_promotion.DataKeys(e.RowIndex).Item(0).ToString
        Dim cap_min As Decimal = CType(GridView_promotion.Rows(e.RowIndex).Cells(4).Controls(0), TextBox).Text
        Dim cap_max As Decimal = CType(GridView_promotion.Rows(e.RowIndex).Cells(5).Controls(0), TextBox).Text
        Dim cap_dis As Decimal = CType(GridView_promotion.Rows(e.RowIndex).Cells(7).Controls(0), TextBox).Text


        If InsertProduct(cap_product_id, cap_min, cap_max, cap_dis) Then
                            Using sqlconn As New OleDbConnection(ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)
                    Dim cmd As New OleDbCommand()
                    cmd.Connection = sqlconn
                    'product = ?,
                    cmd.CommandText = "UPDATE promotion SET  min_price = ?, max_price = ?, discount = ? WHERE promotion_id = ?"
                    cmd.CommandType = CommandType.Text

                    Dim strpromotion_id As String = GridView_promotion.DataKeys(e.RowIndex).Item(0).ToString
                    Dim a As TextBox = GridView_promotion.Rows(e.RowIndex).Cells(4).Controls(0)
                    '  Dim strproduct As String = CType(GridView_promotion.Rows(e.RowIndex).Cells(3).Controls(0), TextBox).Text
                    Dim strminP As Decimal = CType(GridView_promotion.Rows(e.RowIndex).Cells(4).Controls(0), TextBox).Text
                    Dim strmaxP As Decimal = CType(GridView_promotion.Rows(e.RowIndex).Cells(5).Controls(0), TextBox).Text
                    Dim strDis As Decimal = CType(GridView_promotion.Rows(e.RowIndex).Cells(7).Controls(0), TextBox).Text


                    '  cmd.Parameters.Add("@p_product", OleDbType.VarChar).Value = strproduct
                    cmd.Parameters.Add("@p_min", OleDbType.Decimal).Value = strminP
                    cmd.Parameters.Add("@p_max", OleDbType.Decimal).Value = strmaxP
                    cmd.Parameters.Add("@p_dis", OleDbType.Decimal).Value = strDis
                    cmd.Parameters.Add("@p_id", OleDbType.Integer).Value = strpromotion_id
                    sqlconn.Open()
                    cmd.ExecuteNonQuery()
                    sqlconn.Close()
                End Using
                GridView_promotion.EditIndex = -1
                BindGridView()
                lblAdd.Visible = True
          
        Else
            Response.Write("โปรโมชั่นซ้ำ!!! ลองใส่ใหม่อีกทีละกัน ")

        End If
        


    End Sub

Dim comm2 As String
        comm2 = " UPDATE promotion"
        comm2 += " SET min_price = '" & 501 & "' , max_price = '" & 1002 & "', discount = '" & CapDiscount & "' "
        comm2 += " FROM promotion "
        comm2 += " where promotion_id = '" & A11 & "' "
        comm2 += " and   min_price and =" & 500 
        comm2 += " and   max_price and =" & 1000