小编MIc*_*vid的帖子

我有一个方法,可以从db计算每个月的总金额,如图所示.

 public static List<Sale> ChartMonthlySalePerYear()
    {
        using (SQLiteConnection con = new SQLiteConnection(Connection.DatabaseLocationString))
        {
            SQLiteCommand cmd = null;
            string query = String.Format("SELECT  strftime('%m', SaleDate)  AS  month,  SUM(AmountPaid)  AS  sum_amountpaid   FROM  {0}   WHERE   strftime('%Y', SaleDate)  =  @1  GROUP BY   strftime('%m', SaleDate)  ", Sale.TABLE_NAME);
            cmd = new SQLiteCommand(query, con);
            cmd.Parameters.Add(new SQLiteParameter("@1", Properties.Settings.Default.ChartYearlyDisplay));
            con.Open();
            SQLiteDataReader reader = cmd.ExecuteReader();

            var list = new List<Sale>();
            while (reader.Read())
            {
                Sale value = new Sale()
                {
                    Months = reader["month"].ToString(),
                    SUMAmountPaid = Convert.ToDecimal(reader["sum_amountpaid"])
                };
                list.Add(value);
            }
            con.Close();

            return list; …