H guys,
I just faced a probelm with my code.It raises an exception.This is the code.

conn = oSubPayItemDescription.GetDbConnection()
            cmd = New OleDbCommand("SELECT [sub_pay_item_quantity].[quantity],[sub_pay_item_unit_rate].[rate] FROM " &
                                   "[sub_pay_item_quantity],[sub_pay_item_unit_rate] WHERE [sub_pay_item_quantity].[sub item]=[sub_pay_item_unit_rate].[sub item] AND " &
                                   "[sub_pay_item_quantity].[sub item]='" & subItem & "' AND [sub_pay_item_quantity].[bridge type]='" & bridgeType & "' " &
                                   "AND [sub_pay_item_quantity].[span]='" & span & "'", conn)

            data_reader = cmd.ExecuteReader()
            If data_reader.HasRows = True Then
                Do While data_reader.Read()
                    payItem = CDbl(data_reader.Item("pay item"))
                    subpayItem = CDbl(data_reader.Item("sub pay item"))
                    subItem = data_reader.Item("sub item")
                    unit = data_reader.Item("unit")
                    bridgeType = data_reader.Item("bridge type")
                    span = (data_reader.Item("span").ToString())
                    quantity = CDbl(data_reader.Item("quantity"))
                    rate = CDbl(data_reader.Item("rate"))

                    RichTextBox1.AppendText(payItem & vbTab & vbTab & " " & " " & subpayItem & vbTab & vbTab & subItem & vbTab & vbTab & " " & _
                                          unit & vbTab & vbTab & " " & " " & " " & " " & bridgeType & vbTab & vbTab & " " & span & vbTab & _
                                            "" & vbTab & " " & quantity & vbTab & rate & vbNewLine)
                Loop
            Else
                MsgBox("Unit rate does not exist", vbCritical, "Bridge Construction Cost Estimate")
            End If

It raises the exception when it reaches the do while loop indicating at pay item.

Hi,

Your SELECT statement that is run in the command is only selecting quantity and rate so the datareader will only have quantity and rate fields.

Ofcourse G Waddell,i fixed it by writing another query.Thanks

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