Linq查询没有给出预期的结果

Question

我正在努力构建一个提供单个最小值的linq查询。但是，我一直得到错误的最小值。我确定这是一个连接问题，但我无法获得一个外连接的工作。我已经尝试了一些基于其他职位的外部连接，但无法做任何工作。我不确定我需要外部连接来完成这项工作。我想我已经尝试过，我认为我可以组合每一个组合。

这里是我开始查询：

(from r in Results 
    join entry in Entries on r.EntryId equals entry.EntryId 
    join entryEvent in EntryEvents on entry.EntryId equals entryEvent.EntryId 
    join eswimmer in EntrySwimmers on entry.EntryId equals eswimmer.EntryId 
    where eswimmer.SwimmerId == 12027 && entryEvent.EventNumberId == 1233 
    select r.Time) 
.Min(); 

外连接尝试：

from r in Results 
join en in Entries on r.EntryId equals en.EntryId 
join ev in EntryEvents on en.EntryId equals ev.EntryId into evJoined 
join s in EntrySwimmers on en.EntryId equals s.EntryId into sJoined 
from ev in evJoined.DefaultIfEmpty() 
from s in sJoined.DefaultIfEmpty() 
where (s.SwimmerId == 12027 && ev.EventNumberId == 1233) 
select r.Time; 

的问题是，我得到的所有结果最小值为游泳而不是该游泳者的最小值和特定事件。

的阶级结构是这样的：

结果

public int ResultId 
public int EntryId 
public ICollection<Entry> Entry 
public int EntryEventId 
public ICollection<EntryEvent> EntryEvent 
public TimeSpan Time 

项

public int EntryId 
public ICollection<EntrySwimmer> EntrySwimmers 
public Result Results 
public ICollection<EntryEvent> EntryEvents 

EntryEvents

public int EntryEventId 
public int EventNumberId 
public EventNumber EventNumbers 
public int EntryId 
public Entry Entry 

EntrySwimmers

public int EntryId 
public Entry Entries 
public int SwimmerId 
public Swimmer Swimmers 

我还在学习关于linq，连接等等，所以感谢解释。先谢谢你！

Answer 1

您已经拥有了导航属性映射所以基本上你不需要任何连接，因为你的ORM将覆盖为你：

var min = Results 
      .Include(x => x.Entry.Select(y => y.EntrySwimmers)) //here you should rename Entry to Entries ideally in your result class 
      .Include(x => x.Entry.Select(y => y.EntryEvents)) 
      .Where(x => x.Entry.EntrySwimmers.Any(y => y.SwimmerId == 12027) && x.EntryEvents.Any(y => y.EventNumberId == 1233))    
      .Min(x => x.Time); 

不知道为什么你有两个在结果和条目，虽然活动。