linq 谁能帮我把这sql改成linq啊，谢谢了。

SQL code

select * from [train] where id in(select trainid from [UserTrain] where userid='92' and  trainid is not null);

------解决方案--------------------

探讨

SQL code
select * from [train] where id in(select trainid from [UserTrain] where userid='92' and trainid is not null);

------解决方案--------------------
var query=from t in db.train
let temp=db.UserTrain.Where(u=>u.userid=="92" && !Nullable<int>.Equals(u.trainid,null)).Select(u=>u.trainid)
where temp.Contains(t.id)
select t;
------解决方案--------------------
FROM TB IN TABLE WHERE SELECT
语法这样 仿造语法自己改改吧 楼上也可以 18素材为你提供
------解决方案--------------------
IQueryable iqa=from t in db.Trains
join ut in db.UserTrains on t.Id equals ut.TrainId
where ut.UserId==92 &&ut.TrainId!=null
select new{id=t.id,AliasName=t.AliasName};


------解决方案--------------------
IQueryable iqa=from t in db.Trains
join ut in db.UserTrains on t.Id equals ut.TrainId
where ut.UserId==92 &&ut.TrainId!=null
select t;
ddl_trainclass.DataSource = iqa.toList();
ddl_trainclass.DataBind();
ddl_trainclass.DataValueField = "id";
ddl_trainclass.DataTextField = "AliasName";