public static DataSet GetPPriceList(string aircompany, string departPort, string arrivePort, string cabin,Boolean flag=false)

        {

            string sql = "SELECT ID, AirCompany,DepartCode,ArriveCode,ServerGrade,Cabin,Price,Agio,SaleBeginTime,SaleEndTime,TravelBeginTime,TravelEndTime FROM PPrice WHERE `Status`=1 AND SaleEndTime>NOW() AND TravelEndTime>NOW()  ";

            if (aircompany != "")

            {

                sql += " and AirCompany='" + aircompany + "' ";

            }

            if (departPort != "")

            {

                sql += " and DepartCode='" + departPort + "' ";

            }

            if (arrivePort != "")

            {

                sql += " and ArriveCode='" + arrivePort + "' ";

            }

            if (cabin != "")

            {

                sql += " and Cabin='" + cabin + "'";

            }

            sql += " ORDER BY ModifyTime DESC ";

            DataSet ds = null;

            using (MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection(MySqlHelper.ConnectionString))

            {

                if (ConnectionState.Open != conn.State)

                    conn.Open();

                if (flag)

                {

                    MySql.Data.MySqlClient.MySqlTransaction tra = conn.BeginTransaction(IsolationLevel.ReadUncommitted);

                    ds = MySqlHelper.ExecuteDataset(tra, CommandType.Text, sql);

                    tra.Commit();

                }

                else

                {

                    ds = MySqlHelper.ExecuteDataset(conn, CommandType.Text, sql);

                }

            }

            return ds;

        }