家長和孩子有關作爲循環滿耳

Question

我有數據如下

A  B 
1001 601 
1002 1001 
1003 1002 
1004 1002 
1005 1002 

我需要輸出

1001 
1002 
1003 
1001 
1002 
1004 
1001 
1002 
1005 

請幫我

Answer 1

試試下面的代碼。

WITH sample_data AS(
    SELECT '1001' A, '601' B FROM dual UNION ALL 
    SELECT '1002' A, '1001' B FROM dual UNION ALL 
    SELECT '1003' A, '1002' B FROM dual UNION ALL 
    SELECT '1004' A, '1002' B FROM dual UNION ALL 
    SELECT '1005' A, '1002' B FROM dual 
) 
SELECT TRIM(COLUMN_VALUE) tree_path 
FROM 
(
    SELECT SUBSTR(SYS_CONNECT_BY_PATH(A, ','),2) tree_path 
    FROM sample_data 
    WHERE CONNECT_BY_ISLEAF = 1 
    start with A = '1001' 
    CONNECT BY PRIOR A = B 
), XMLTABLE(('"' || REPLACE(tree_path, ',', '","') || '"'))