Question

OleDbConnection myAccessConn = myAccessConnection();
        OleDbCommand myAccessCommand = new OleDbCommand();
        DataSet myDataSet = new DataSet();

        string orderId = null, Checkintime=null, RoomPrice=null, ReceiptNo=null;
        decimal totalfoodamount = 0;

        try
        {
            myAccessConn.Open();

            DateTime startTime = DateTime.Now.ToLocalTime();
            DateTime dateOnly = startTime.Date;
            DateTime endDateOnly = DateTime.Now.AddDays(1).ToLocalTime().Date;

            string sqlStatement = "select ID,Checkintime, RoomPrice, OrderNo from Orders where RoomType='" + selectedRoom.Key + "' and RoomNumber =" + selectedRoom.Value + " and Checkintime between '" + dateOnly +"' and '"+endDateOnly+"'";
            myAccessCommand = new OleDbCommand(sqlStatement, myAccessConn);
            OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myAccessCommand);
            myDataAdapter.Fill(myDataSet, "Orders");

            DataTableCollection dta = myDataSet.Tables;
            DataColumnCollection drc = myDataSet.Tables["Orders"].Columns;
            DataRowCollection dra = myDataSet.Tables["Orders"].Rows;

            foreach (DataRow dr in dra)
            {
                orderId= dr[0].ToString();
                Checkintime= dr[1].ToString();
                RoomPrice= dr[2].ToString();
                ReceiptNo= dr[3].ToString();
                Console.WriteLine("orderid: "+orderId+", Checkintime:  "+Checkintime+", RoomPrice: "+RoomPrice+", ReceiptNo: "+ReceiptNo+"");

            }

我尝试过这种方法，但它显示了一个例外：{＆＃34;标准表达式中的数据类型不匹配。＆＃34;}因此它不会在不同的日期挑出2个相同的时间。

Answer 1

目前尚不清楚你在问题和代码中都没有尝试做什么。但是代码有潜在的错误，你没有使用参数，而是使用+ ... +制作一个SQL字符串，这是一个禁忌。我修改了部分代码但由于无法理解你在做什么而无法进一步：

DateTime startTime = DateTime.Now.ToLocalTime().Date;
DateTime endTime = DateTime.Now.AddDays(1).ToLocalTime().Date;

string sqlStatement = @"select ID,Checkintime, RoomPrice, OrderNo 
   from Orders 
   where RoomType=@roomType and 
   RoomNumber = @roomNumber and 
   Checkintime >= @start and CheckinTime < @end";

myAccessCommand = new OleDbCommand(sqlStatement, myAccessConn);
myAccessCommand.Parameters.AddWithValue("@roomType", selectedRoom.Key);
myAccessCommand.Parameters.AddWithValue("@roomNumber", selectedRoom.Value);
myAccessCommand.Parameters.AddWithValue("@start", startTime);
myAccessCommand.Parameters.AddWithValue("@end", endTime);

OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myAccessCommand,myAccessConn);
myDataAdapter.Fill(myDataSet, "Orders");

如何从c＃中的访问数据库中获取唯一的超时时间

1 个答案: