我需要創建LINQ到實體SQL查詢

Question

我有模型

public class GrandPrix 
{ 
    public int Id { get; set; } 

    [Required] 
    [Display(Name = "Имя")] 
    [DataType(DataType.Text)] 
    public string Name { get; set; } 

    public int LocationId { get; set; } 

    public int? ChampionchipId { get; set; } 

    public virtual Location Location { get; set; } 
    public virtual Championchip Championchip { get; set; } 
} 
    public class Location 
{ 
    public int Id { get; set; } 

    [Required] 
    [Display(Name = "Location")] 
    [DataType(DataType.Text)] 
    public string Name { get; set; } 

// public virtual ICollection<GrandPrix> GrandPrix { get; set; } 
} 

我需要

ViewBag.LocationId = new SelectList(db.Locations, "Id", "Name"); 

db.Locations 修改。凡（L => l.id不包含在db.Grandprix.Where（G => g.ChampionchipId == 1））

此查詢它的工作

SELECT Locations.Id as Id, Locations.Name as Name FROM dbo.Locations WHERE Locations.Id Not In (SELECT GrandPrixes.LocationId FROM GrandPrixes WHERE ChampionchipId = 1) 

對不起，我的英語和感謝您的幫助。

Answer 1

db.Locations.Where(loc=>loc.GrandPrixes.Any(gp=>gp.ChampionshipId != 1)) 

如果您的FK關係設置正確，應該爲您提供位置信息。

否則

var gps = db.GrandPrixes.Where(gp=>gp.ChampionshipId == 1) 
         .Select(gp=>gp.Location.LocationId).ToList(); 
db.Locations.Where(loc=>!gps.Any(gp=>gp == loc.LocationId))