Linq - 如何在没有 'join' 关键字的情况下构建此查询？

Question

我有以下部分 Linq 查询:

var query = from ri in RouteInstance
        join rir in RouteInstanceRules on ri.RouteInstanceID equals rir.RouteInstanceID
        join rl in RoutingLocation on rir.RoutingLocationID equals rl.RoutingLocationID
        join rlh in RoutingLocationHistory on rl.RoutingLocationID equals rlh.RoutingLocationID
        where rlh.RouteTakenTime >= new System.DateTime(2011,2,4) && rlh.RouteTakenTime <= new System.DateTime(2011,2,5)

There is a 1:M relationship between RouteInstance and RouteInstanceRules
There is a 1:M relationship between RouteInstanceRules and RoutingLocation
There is a 1:M relationship between RoutingLocation and RoutingLocationHistory

由于这些关系是使用 FK 强制执行的，因此为 L2S 所知，我应该能够在不使用“join”关键字的情况下构建此查询。但是，我对如何做到这一点感到困惑。

谢谢。

Answer 1

你到底想要 RouteInstances 吗？如果是这样的话:

var query = DataContext.RoutingLocationHistory
           .Where(rlh => rlh.RouteTakenTime >= new System.DateTime(2011,2,4) 
                        && rlh.RouteTakenTime <= new System.DateTime(2011,2,5))
           .Select(rlh => rlh.RoutingLocation.RouteInstanceRule.RouteInstance)
           .Distinct();