Question

Can anyone help me with the equivalent LINQ query for the SQL below? I am new to LINQ

Select * From Students_History SH
Where SH.Active = 1 and SH.ModifiedAt in (
select MAX(SH1.ModifiedAt)from Students_History SH1
group by SH1.StudentId)

这是我所尝试的。

var q = 
    from h in Students_History
    where h.Active=1
    group h by h.StudentId into g
    select new 
    {
        StudentID = g.Key,
        LatestModified = g.Max (x => x.ModifiedAt)
    }

这里的争 que没有给我带来正确的结果,有些情况却忽视了积极标准。

我有大约十几个领域: 历史表和我希望所有这些领域不仅仅是学生。 Id and ModedAt.

Answer 1

为此:

var q =
    from hg in Students_History
    group hg by hg.StudentId into g
    join h in Students_History on g.Key equals h.StudentId
    where h.Active == 1 && h.ModifiedAt == g.Max(x => x.ModifiedAt)
    select new
    {
        StudentID = h.StudentId,
        LatestModified = h.ModifiedAt
    }

Answer 2

您需要使用=>运营商进行比较。

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