问LINQ Concat嵌套查询排序

EN

var comp = db.Companies.Select(x => new
        {

            topid = x.ID_comp,
            hill = ((from company in db.Companies
                    where x.ID_comp > company.ID_comp
                    orderby company.ID_comp
                    select new { h = company.ID_comp.ToString() })
                    .Concat((
                    from company in db.Companies
                    where x.ID_comp > company.ID_comp
                    orderby company.ID_comp descending
                    select new { h = company.ID_comp.ToString() })))
                    .Select(y => y.h)
        });

ID_comp | name
--------------------
   1    |Don_avia  
   2    |Aeroflot  
   3    |Dale_avia 
   4    |air_France
   5    |British_AW

1:
2: 1 1
3: 1 2 1 2
4: 1 2 3 1 2 3
5: 1 2 3 4 1 2 3 4

SELECT 
[Extent1].[ID_comp] AS [ID_comp], 
[Project3].[C2] AS [C1], 
[Project3].[C1] AS [C2]
FROM  [dbo].[Company] AS [Extent1]
OUTER APPLY  (SELECT 
    [UnionAll1].[C1] AS [C1], 
    1 AS [C2]
    FROM  (SELECT 
         CAST( [Extent2].[ID_comp] AS nvarchar(max)) AS [C1]
        FROM [dbo].[Company] AS [Extent2]
        WHERE [Extent1].[ID_comp] > [Extent2].[ID_comp]
    UNION ALL
        SELECT 
         CAST( [Extent3].[ID_comp] AS nvarchar(max)) AS [C1]
        FROM [dbo].[Company] AS [Extent3]
        WHERE [Extent1].[ID_comp] > [Extent3].[ID_comp]) AS [UnionAll1] ) AS [Project3]
ORDER BY [Extent1].[ID_comp] ASC, [Project3].[C2] ASC