我正在编写一个存储过程,它应该返回结果,同样的结果将作为输入传递给存储过程,并且在任何特定时间输入和输出相同后递归应该停止。
下面是存储的过程/函数和运行命令(存储过程的新增内容)。
CREATE FUNCTION dbo.Ancestors (@List VARCHAR(MAX))
RETURNS TABLE
AS
RETURN
WITH CTE AS
(
SELECT DISTINCT Child AS RESULT FROM example WHERE Parent IN( SELECT Id =
Item FROM dbo.SplitInts(@List, ',')) or child IN (SELECT Id = Item FROM
dbo.SplitInts(@List, ','))
UNION ALL
SELECT DISTINCT Parent AS RESULT FROM example WHERE Parent IN( SELECT Id =
Item FROM dbo.SplitInts(@List, ',')) or child IN (SELECT Id = Item FROM
dbo.SplitInts(@List, ','))
)
SELECT RESULT FROM CTE
UNION
SELECT RESULT FROM CTE
GO
CREATE PROCEDURE GetAncestors (@thingID VARCHAR(MAX))
AS
SELECT RESULT FROM dbo.Ancestors(@thingID)
GO
EXEC GetAncestors @thingID = '100'
结果是 - ' 100,101'
EXEC GetAncestors @thingID = '100,101'
结果是 - ' 100,101,102'
EXEC GetAncestors @thingID = '100,101,102'
结果是 - ' 100,101,102'
我实际想要的是通过传递100或101或102
来一次性给出结果结果应为 - ' 100,101,102'
以下是示例表:
| Parent | Child |
|---------------------|------------------|
| 100 | 101 |
|---------------------|------------------|
| 101 | 102 |
|---------------------|------------------|
答案 0 :(得分:1)
看起来你需要一个简单的递归查询,从给定节点开始遍历树。 CTE
返回对(Parent, Child)
对的列表,因此我将它们组合在一起以获取单个节点的列表(并在此过程中删除重复项)。
请注意,查询是递归的。 CTE(公用表表达式)引用自身。
示例数据
我添加了几行来实际查看正在发生的事情。
DECLARE @T TABLE (Parent int, Child int);
INSERT INTO @T VALUES
(100, 101),
(101, 102),
(102, 103),
(103, 104),
(101, 108),
(108, 109),
(208, 209),
(209, 210);
<强>查询强>
WITH
CTE
AS
(
SELECT
Parent, Child
FROM @T
WHERE Parent = 100
UNION ALL
SELECT
T.Parent, T.Child
FROM
CTE
INNER JOIN @T AS T ON T.Parent = CTE.Child
)
SELECT
Parent AS Result
FROM CTE
UNION
SELECT
Child AS Result
FROM CTE
;
<强>结果强>
Result
100
101
102
103
104
108
109
您可以将查询放在存储过程中,如下所示:
CREATE PROCEDURE GetAncestors(@thingID int)
AS
BEGIN
SET NOCOUNT ON;
WITH
CTE
AS
(
SELECT
Example.Parent, Example.Child
FROM Example
WHERE Parent = @thingID
UNION ALL
SELECT
Example.Parent, Example.Child
FROM
CTE
INNER JOIN Example ON Example.Parent = CTE.Child
)
SELECT
Parent AS Result
FROM CTE
UNION
SELECT
Child AS Result
FROM CTE
;
END
GO