SQL Server查詢 - N的後支點迭代

Question

我有2列的表格：

'Employee'    'ReportsTo' 
1        
2       1 
3       1 
4       2 
5       2 
6       3 
7       3 
8       4 
9       4 
10       5 

我想回到這樣的：

'Employee' 'Reporting Officer' 
1   2,3,4,5,6,7,8,9,10 
2   4,5,8,9,10 
3   6,7 
4   8,9 
5   10 
6 
7 
8 
9 
10 

Answer 1

這將您的示例表，但無法正常工作與這樣的表（將需要更復雜的查詢）：

Employee ReportsTo 
-------- --------- 
12  13 
13  12 

而且它不被稱爲「n次迭代後的透視」。

with cte as (
    SELECT 1 Employee,0 ReportsTo UNION ALL 
    SELECT 2,1 UNION ALL 
    SELECT 3,1 UNION ALL 
    SELECT 4,2 UNION ALL 
    SELECT 5,2 UNION ALL 
    SELECT 6,3 UNION ALL 
    SELECT 7,3 UNION ALL 
    SELECT 8,4 UNION ALL 
    SELECT 9,4 UNION ALL 
    SELECT 10,5 
), 

cte2 as (
    SELECT ReportsTo e,Employee ro FROM cte 
    UNION ALL 
    SELECT a.e,b.Employee FROM cte2 a JOIN cte b ON a.ro = b.ReportsTo 
) 

SELECT 
    Employee, 
    ISNULL(LEFT(ro,LEN(ro)-1),'') as "Reporting Officer" 
FROM (
    SELECT 
    Employee, 
    REPLACE(REPLACE((
     SELECT ro FROM cte2 x WHERE x.e=cte.Employee ORDER BY 1 FOR XML PATH('') 
    ),'<ro>',''),'</ro>',',') ro 
    FROM cte 
) a 

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