Hi I am new to c# and here is the problem, I have a column named "no\_of\_available\_item". I need to get its value subtracted by the value from a text box and their difference will be input again in my column no\_of\_available\_item, this code does not work , any help ?thank so much in advance.

```
public void Borrow_select(int intBorrow)
    {
        string str_Query;
        str_Query = "SELECT * FROM tbl_item  WHERE id = ' + myID + '";
        DbCmd = new MySqlCommand(str_Query, DbCn);
        DbRead = DbCmd.ExecuteReader();
        while (DbRead.Read())
        {
            no_of_available_item = Convert.ToInt16( DbRead["no_of_available_item"]);
            int_result = no_of_available_item - intBorrow;

            str_Query = "UPDATE tbl_item SET no_of_available_item = '" + int_result + "' WHERE id = '" + myID + "'";              
        }  
    }

```