我需要将此SQL语句移植到LINQ：

SELECT f.ID as IdFlight, 
       Tarif * 1 as Tarif, 
       f.Time, f.TimeOfArrival, 
       sl.Name as FromLoc, 
       sl.Country as FromCountry, 
       sl.Airport as FromAirport,
       dl.Name as ToLoc, 
       dl.Country as ToCountry, 
       dl.Airport as ToAirport 
FROM Flights as f 
    INNER JOIN Locations as sl ON sl.ID = f.ID_Source  
    INNER JOIN Locations as dl ON dl.ID = f.ID_Destination 
    INNER JOIN FlightsTarifs as ftf ON f.Id = ftf.IDFlight 
WHERE f.ID_Destination =30005 AND f.Time <= DATEADD(day,4,'2018/05/24 00:00') 
AND f.Time >= '2018/05/24 00:00' ORDER By f.Time, Tarif

我在Linq中的尝试：

IQueryable qinfo = from f in context.Flights
                   join sl in context.Locations on f.Id_Source equals sl.ID
                   join dl in context.Locations on f.Id_Destination equals dl.ID
                   join ftf in context.FlightsTarifs on f.ID equals ftf.IDFlight
                   where (f.Id_Source == aFormUser.FlightSrcID)
                   where (f.Id_Destination == aFormUser.FlightDestID)
                   where (f.Time.Date >= aFormUser.DepartureDate.Date)
                   where (f.Time.Date <= aFormUser.DepartureDate.Date.AddDays(4))
                   orderby f.Time, ftf.Tarif
                   select new {f.ID, ftf.Tarif, f.Time, f.TimeOfArrival,
                               sl.Name, sl.Country, sl.Airport,
                               dl.Name, dl.Country, dl.Airport  };

我现在有一些问题要解决：
1.由于我将表flights与表locations连接了两次，以便获得源位置和目的地位置的名称，因此在LinQ中这样做会导致编译器错误，即dl.Name、dl.Country、dl、Airport是匿名类型，它们最终将与其他sl.Name、sl.Country、sl. Airport具有相同的名称。
1.我不能像在Sql中那样使用“As”表达式，或者在Linq中是否有等效的表达式？
1.当我在linq查询中时，我不能将Tarif乘以乘客数量，因为它不允许我这样做。