on子句linq中的多个条件

Question

我希望通过LINQ实现以下SQL语句，但对于

则无法成功

   DECLARE @_Date datetime = '2014-02-25'
    SELECT  Title,FromDate,ToDate
    FROM    Positions INNER JOIN
           PositionHistories ON Positions.PositionID = PositionHistories.PositionID
           and @_Date BETWEEN FromDate and ToDate
where PositionID=58

当我编写以下LINQ查询时

    from p in db.Positions 
    join ph in PositionHistories.where((x => x.FromDate <= _Date && x.ToDate >= _Date)
    on p.PositionID equals ph.PositionID
    where p.PositionID=58
select new
    {
     Title,
    FromDate,
    ToDate
    }

我得到以下SQL输出

SELECT  Title,FromDate,ToDate
FROM    Positions INNER JOIN       
PositionHistories ON Positions.PositionID = PositionHistories.PositionID              
where PositionID=58  and @_Date BETWEEN FromDate and ToDate

这是不希望的。任何建议