title: VB.NET and MySql UPDATE query
body: <p>I have my codes here without errors (at least not when I Debug it, I use <code>VS 2010</code>), 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 <code>VB.NET</code> <code>Datagridview</code> or <code>MySql Database</code> 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.</p>
  
  <pre><code>        cmd.Connection = conn
  
          Dim Result = "Quantity" + txtQty.Text
  
          cmd.CommandText = " UPDATE incomingdeliveries SET Quantity ='" &amp; Result &amp; "';"
          cmd.Parameters.Add(New MySqlParameter("@Quantity", txtQty.Text))
  
          cmd.ExecuteNonQuery()
  
          MsgBox("Data Added to the Database")
  
              Me.IncomingdeliveriesTableAdapter.Dispose()
          Me.IncomingdeliveriesTableAdapter.Fill(Me.IncomingDeliveriesDataSet.incomingdeliveries)
  
              lblCode.Text = ("Tables Refreshed!")
  </code></pre>