Is there any way to write LINQ (or with procedural style) query, that can select all children with one SQL query?

I have entity:

public class Comment
{
   public int Id {get;set;}
   public int ParentId {get;set;}
   public int Text {get;set;}
}

I have a ID, so I want to select Comment with ID and all its children with subchildren.

Example:

1
-2
--3
-4
-5
--6

2
3

If ID == 1 then I want list of 1,2,3,4,5,6.