由网友(稚氣)分享简介：考虑以下的行中一个数据库：Consider the following rows in a database:Id | Parent__________________1 null2 13 24 35...

考虑以下的行中一个数据库：

Consider the following rows in a database:

Id      |   Parent
__________________
1           null
2           1
3           2
4           3
5           null
6           5

每个编号具有空 父是所有者/超级家长。

Each Id that has a null Parent is the "Owner"/"Super Parent".

什么是最好的办法，表现智慧，收集父母和他们的孩子？我应该使用 LINQ 或存储过程

What would be the best approach, performance wise, to collect the parents and their children ? Should I use LINQ or Stored Procedures ?

我想最终的结果是的IEnumerable＆LT; IEnumerable的＆LT; INT＆GT;＆GT;

推荐答案

在SQL中，你可以使用查询的CTE。例如，检索与其父节点的列表，并在其树的最高父

In SQL, you could query using a CTE. For example, to retrieve a list of nodes with their parent and the highest parent in their tree:

declare @t table (id int, parent int)
insert @t (id, parent) values (1, null), (2,1), (3,2), (4,3), (5,null), (6,5)

; with cte as (
    select  id, parent, id as head
    from    @t
    where   parent is null
    union all
    select  child.id, child.parent, parent.head
    from    @t child
    join    cte parent
    on      parent.id = child.parent
)
select  *
from    cte

这给了：

id  parent  head
1   NULL    1
2   1       1
3   2       1
4   3       1
5   NULL    5
6   5       5

请注意，我改变你的例子数据，所以第2行，不再是自己一个孩子，但第1行的孩子。

Note that I changed your example data so row 2 is no longer a child of itself, but a child of row 1.