我有一个层次结构Hive表，有两列，Parent和Child。 我需要获取与父记录关联的所有后代的列表。请注意 Hive / Imapala不支持递归SQL。
Source Table
+----+-----------+
| Parent | Child |
+----+-----------+
| a | b |
| b | c |
| c | d |
| d | e |
| e | f |
| f | x |
+----+-----------+
Expected Result:
+----+-----------+
| Parent | Child |
+----+-----------+
| a | b | // As b is the child of a, all the descendants of b
| a | c | // are also descendants of a.
| a | d |
| a | e |
| a | f |
| a | x |
| b | c | // As c is the child of b, all the descendants of c
| b | d | // are also descendants of b.
| b | e |
| b | f |
| b | x |
| c | d |
| c | e |
| c | f |
| c | x |
| d | e |
| d | f |
| d | x |
| e | f |
| e | x |
| f | x |
+----+-----------+
谢谢！