我对SQL Server 2005中的性能有一个较大的查询

Question

我对SQL Server 2005中的性能有一个很大的疑问。

我有这样的数据

id  parentId
1   null
2   1
3   1
4   2
5   4
6   3

我想要下划线的记录顺序与parentId和id明智

id  Order
1   1
2   2
4   3
5   4
3   5
4   6

我不想使用循环，因为如果行数过多，循环会造成问题。 请给我一个简单的方法来完成它，并损害性能。

更新，请运行下面的脚本

create table [mytable] ( [id] int, [parentId] int ) GO

INSERT INTO [mytable] ([id],[parentId])VALUES(1,NULL) INSERT INTO [mytable] ([id],[parentId])VALUES(2,6) INSERT INTO [mytable] ([id],[parentId])VALUES(4,9) INSERT INTO [mytable] ([id],[parentId])VALUES(5,4) INSERT INTO [mytable] ([id],[parentId])VALUES(6,13) INSERT INTO [mytable] ([id],[parentId])VALUES(7,13) INSERT INTO [mytable] ([id],[parentId])VALUES(8,5) INSERT INTO [mytable] ([id],[parentId])VALUES(9,1) INSERT INTO [mytable] ([id],[parentId])VALUES(13,1) GO

; WITH q AS ( SELECT id, parentId, CAST(id AS VARCHAR(MAX)) + '/' AS path FROM mytable WHERE parentId IS NULL UNION ALL SELECT t.id, t.parentId, q.path + CAST(t.id AS VARCHAR(MAX)) + '/' FROM q JOIN mytable t ON t.parentId = q.id ) SELECT *, ROW_NUMBER() OVER (ORDER BY path) AS rn FROM q ORDER BY path GO

The result of this query ID ParentId Path rn 1 NULL 1/ 1 13 1 1/13/ 2 6 13 1/13/6/ 3 2 6 1/13/6/2/ 4 7 13 1/13/7/ 5 9 1 1/9/ 6 4 9 1/9/4/ 7 5 4 1/9/4/5/ 8 8 5 1/9/4/5/8/ 9


  

但是我想从结果中得到rn的结果，首先是1，然后是1/9，然后是1/9 / ...，然后是1/13 /，然后是1/13 /...。请给我解决方案。

我想要类似的结果

ID    ParentId  Path     rn 
1   NULL    1/       1 
13  1   1/13/       6 
6   13  1/13/6/      7 
2   6   1/13/6/2/    8
7   13  1/13/7/      9
9   1   1/9/         2 
4   9   1/9/4/       3 
5   4   1/9/4/5/     4 
8   5   1/9/4/5/8/   5 

---

WITH    q AS 
        ( 
        SELECT  id, parentId, CAST(id AS VARCHAR(MAX)) AS path 
        FROM    mytable 
        WHERE   parentId IS NULL 
        UNION ALL 
        SELECT  t.id, t.parentId, q.path + '/' + CAST(t.id AS VARCHAR(MAX)) 
        FROM    q 
        JOIN    mytable t 
        ON      t.parentId = q.id 
        ) 
SELECT  *, ROW_NUMBER() OVER (ORDER BY path) AS rn 
FROM    q 
ORDER BY 
        path 

在上面还有一个问题。 您正在使用按路径排序，假设记录是1/13和1/2的情况，那么order by是1/13和1/2的结果，但是我想要1/2的顺序然后1/13 ，因为2小于13。

Answer 1

WITH    q AS
        (
        SELECT  id, parentId, CAST(id AS VARCHAR(MAX)) + '/' AS path
        FROM    mytable
        WHERE   parentId IS NULL
        UNION ALL
        SELECT  t.id, t.parentId, q.path + CAST(t.id AS VARCHAR(MAX)) + '/'
        FROM    q
        JOIN    mytable t
        ON      t.parentId = q.id
        )
SELECT  *, ROW_NUMBER() OVER (ORDER BY path) AS rn
FROM    q
ORDER BY
        path

Answer 2

我无法确切说明您的数据库是什么样子，但是这样的工作应该可以

Select id, [Order] From Table1 Order By Order, id

Answer 3

select id, parentid as order from table 
order by coalesce(parentid, 9999), id