我對SQL Server 2005中的性能有一個較大的查詢

Question

我對SQL Server 2005中的性能有一個很大的疑問。

我有這樣的數據

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

我想要下划線的記錄順序與parentId和id明智

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

我不想使用循環，因為如果行數過多，循環會造成問題。 請給我一個簡單的方法來完成它，並損害性能。

更新，請運行下面的腳本

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


  

但是我想從結果中得到rn的結果，首先是1，然后是1/9，然后是1/9 / ...，然后是1/13 /，然后是1/13 /...。請給我解決方案。

我想要類似的結果

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 

在上面還有一個問題。 您正在使用按路徑排序，假設記錄是1/13和1/2的情況，那么order by是1/13和1/2的結果，但是我想要1/2的順序然后1/13 ，因為2小於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

我無法確切說明您的數據庫是什么樣子，但是這樣的工作應該可以

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

Answer 3

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