創建自定義函數或存儲過程

Question

我有一個Hierarchy表Master_id和Sub_id。

sub_id Master_id 
2  1 
3  2 
4  1 
5  3 
6  7 

我想創建一個迭代函數或存儲過程（我不知道我從來沒有使用過任何人之前）來創建一個多個列，給了我的primary_master_Column（PMC）

sub_id Master_id PMC 
2  1   1 
3  2   1 
4  1   1 
5  3   1 
6  7   7 

Answer 1

select 
    Master_id, sub_id, 
    max(PMC) keep(dense_rank first order by lev desc) as PMC 
from 
(
select 
    sub_id as PMC, level lev, 
    connect_by_root(Master_id) as Master_id, 
    connect_by_root(sub_id) as sub_id 
from your_table 
connect by prior sub_id = Master_id 
) 
group by Master_id, sub_id 

fiddle

Answer 2

SQL Fiddle

的Oracle 11g R2架構設置：

CREATE TABLE test (sub_id, Master_id) AS 
      SELECT 2,  1 FROM DUAL 
UNION ALL SELECT 3,  2 FROM DUAL 
UNION ALL SELECT 4,  1 FROM DUAL 
UNION ALL SELECT 5,  3 FROM DUAL 
UNION ALL SELECT 6,  7 FROM DUAL; 

查詢1：

SELECT t.sub_id, 
     t.master_id, 
     CONNECT_BY_ROOT(t.master_id) AS PMC 
FROM test t 
     LEFT OUTER JOIN 
     test x 
     ON (t.master_id = x.sub_id) 
START WITH x.sub_id IS NULL 
CONNECT BY PRIOR t.sub_id = t.master_id 

Results：

| SUB_ID | MASTER_ID | PMC | 
|--------|-----------|-----| 
|  2 |   1 | 1 | 
|  3 |   2 | 1 | 
|  5 |   3 | 1 | 
|  4 |   1 | 1 | 
|  6 |   7 | 7 | 

查詢2：

SELECT t.sub_id, 
     t.master_id, 
     CONNECT_BY_ROOT(t.master_id) AS PMC 
FROM test t 
START WITH NOT EXISTS (SELECT 'x' FROM test x WHERE t.master_id = x.sub_id) 
CONNECT BY PRIOR t.sub_id = t.master_id 

Results：

| SUB_ID | MASTER_ID | PMC | 
|--------|-----------|-----| 
|  2 |   1 | 1 | 
|  3 |   2 | 1 | 
|  5 |   3 | 1 | 
|  4 |   1 | 1 | 
|  6 |   7 | 7 |