我有一个表,它的类型如下:
Id Parent_id Code Name market
1 NULL 1ex name 1 3
2 1 2ex name 2 3
3 1 3ex name 3 3
4 Null 4ex name 4 1
5 null 5ex name 5 3
6 4 6ex name 6 3
我想从上面的表中选择code
和name
,使其按以下方式排序:
- 基于市场id=3的市场
- 父级id
- 相关子 别人
ie。应该先显示id 1 (Parent_id),然后是id 2和3 (Child id)。'parent_id'中的值来自'id'列。
到目前为止,我已经建立了以下查询,我觉得订购父代码和相关的子代码有点困难。
select code,name from tbl_codes A
order by CASE WHEN(A.[Market] = 3) THEN 0 ELSE 1 END
有谁能帮我一下吗
试试这个
SELECT code ,
name
FROM tbl_codes A
ORDER BY CASE WHEN ( A.[Market] = 3 ) THEN 0
ELSE 1
END ,
CASE WHEN ( ISNULL(parent_id,0) = 1 ) THEN 0
ELSE 1
END
递归CTE是构造父/子层次结构的最佳方法,如下所示:
-- Set up test data
CREATE TABLE tbl_codes (id INT , Parent_id INT, Code VARCHAR(3), NAME VARCHAR(12), Market INT)
INSERT tbl_codes
SELECT 1, NULL, '1ex', 'name 1', 3 UNION ALL
SELECT 2, 1 , '2ex', 'name 2', 3 UNION ALL
SELECT 3, 1 , '3ex', 'name 3', 3 UNION ALL
SELECT 4, NULL , '4ex', 'name 4', 1 UNION ALL
SELECT 5, NULL , '5ex', 'name 5', 3 UNION ALL
SELECT 6, 4 , '6ex', 'name 6', 3
CREATE VIEW [dbo].[View_ParentChild]
AS
-- Use a recursive CTE to build a parent/child heirarchy
WITH
RecursiveCTE AS
(
SELECT
id,
name,
parent_id,
Code,
market,
sort = id
FROM
tbl_codes
WHERE
parent_id IS NULL
UNION ALL
SELECT
tbl_codes.id,
tbl_codes.name,
tbl_codes.parent_id,
tbl_codes.Code,
tbl_codes.market,
sort = tbl_codes.parent_id
FROM
tbl_codes
INNER JOIN RecursiveCTE
ON tbl_codes.parent_id = RecursiveCTE.id
WHERE
tbl_codes.parent_id IS NOT NULL
)
SELECT
Code,
NAME,
Market,
Sort
FROM
RecursiveCTE
GO
根据您的要求,我已将查询重构为VIEW。
使用视图:
SELECT
*
FROM
dbo.View_ParentChild AS vpc
ORDER BY
CASE WHEN ( Market = 3 ) THEN 0
ELSE 1
END,
sort
它给出如下结果:
Code NAME Market Sort
---- ------ ------ ----
1ex name 1 3 1
2ex name 2 3 1
3ex name 3 3 1
6ex name 6 3 4
5ex name 5 3 5
4ex name 4 1 4
要了解更多关于递归cte的信息,请点击这里
And是不使用递归CTE的视图的新版本
CREATE VIEW [dbo].[View_ParentChild_v2]
AS
SELECT
id,
Code,
market,
sort
FROM
(
SELECT
id,
name,
parent_id,
Code,
market,
sort = id
FROM
tbl_codes
WHERE
parent_id IS NULL
UNION ALL
SELECT
tbl_codes.id,
tbl_codes.name,
tbl_codes.parent_id,
tbl_codes.Code,
tbl_codes.market,
sort = tbl_codes.parent_id
FROM
tbl_codes
WHERE
tbl_codes.parent_id IS NOT NULL
) AS T
GO
用法如下:
SELECT
*
FROM
View_ParentChild_v2
ORDER BY
CASE WHEN ( Market = 3 ) THEN 0
ELSE 1
END,
sort
注意:第一个版本,使用递归CTE,可以处理几乎无限的父/子级别,而版本2只能处理一个级别。
您可以在列中添加条件。试一试:
SELECT code ,
name ,
CASE WHEN ( A.[Market] = 3 ) THEN 0
ELSE 1
END AS marketOrder ,
CASE WHEN ( parent_id = 1 ) THEN 0
ELSE 1
END AS parentOrder
FROM tbl_codes A
ORDER BY parentOrder ,
marketOrder