VB.NET and MySql UPDATE query

Question

I have my codes here without errors (at least not when I Debug it, I use `VS 2010`), but what I wish to happen is when I click on the add button, the number/s in the textbox(txtQty) would add to the numbers currently saved in the column "Quantity". (ex: txtQty "100" and current on the column is "200", I want to add "100" from the textbox to the column which has "200" and save it as a new number "300". Simple math I know, but the problem is I have yet to know how to use math equations on `VB.NET` `Datagridview` or `MySql Database` This Code executes but when I click Add the numbers in the column return to 0. Any Hint or Tips would be much appreciated, thanks. ``` cmd.Connection = conn Dim Result = "Quantity" + txtQty.Text cmd.CommandText = " UPDATE incomingdeliveries SET Quantity ='" & Result & "';" cmd.Parameters.Add(New MySqlParameter("@Quantity", txtQty.Text)) cmd.ExecuteNonQuery() MsgBox("Data Added to the Database") Me.IncomingdeliveriesTableAdapter.Dispose() Me.Incomingdeliveries…

Accepted Answer

your command text must be parameterized also

```
cmd.CommandText = " UPDATE incomingdeliveries SET Quantity = @iQuantity + Quantity"
cmd.Parameters.Add(New MySqlParameter("@iQuantity", txtQty.Text))
```

UPDATE 1

```
Using _conn As New MySqlConnection("connectionStr here")
    Using _comm As New MySqlCommand()
        With _comm
            .Connection = _conn
            .CommandText = "UPDATE incomingdeliveries SET Quantity = @iQuantity + Quantity"
            .CommandType = CommandType.Text
            .Parameters.AddWithValue("@iQuantity", txtQty.Text)
        End With
        Try
            _conn.Open()
            _comm.ExecuteNonQuery()
        Catch ex As MySqlException
            Msgbox(ex.Message.ToString())
        End Try
    End Using
End Using
```

VB.NET and MySql UPDATE query

Solution

Problem