ORA-00936 缺失運算式

oracle 中 表 expense 的 id是int類型的 ，name是nvarchar2(50)類型，days是int類型的，advance 欄位類型是number(10,2)類型的，

當是在winform中對應的textBox中為空白時，下面的插入語句提示ORA-00936   缺失運算式

煩請大俠幫忙解決啊？急急急！！！不勝感激涕零！！！！

int id = getNum(arrNum, tmp, minValue, maxValue, rd);  //調用方法擷取隨機數作為id欄位的數值。

其中的name,days,advance 表單中是三個textBox的name屬性      。部分主要代碼如下：            

                 try
                 {
                   string sql = string.Format("insert into expense(id,name,days,advance) values({0},'{1}',{2},{3})",id,name.Text.Trim(),days.Text.Trim(),advance.Text.Trim());
                        dbcon.OpenConn();                       
                        OracleCommand cmd = new OracleCommand(sql, conn);
                        cmd.ExecuteNonQuery();
                        cmd.Dispose();
                        MessageBox.Show("添加費用成功!   ", "Photonsoft", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        this.Close();
                    }
                    catch(OracleException oex)
                    {
                        MessageBox.Show(oex.ToString(),"OracleException");
                    }
                    catch(Exception ex)
                    {
                        MessageBox.Show(ex.ToString(), "Photonsoft");
                    }
                    finally
                    {
                        dbcon.CloseConn();
                    }