用sql語句實現

問題如下：
產品結構表
主 元
A B
B C
C D

實現結果如下A->B->C->D

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用with递归

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SELECT 主 from AA
start with 主='A'
 connect by prior 元 = 主

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SQL code:

Connected to Oracle Database 10g Enterprise Edition Release 10.2.0.1.0
Connected as


SQL>
SQL> with table1 as
2 (
3 select 'A' parent1,'B' child1 from dual
4 union all
5 select 'B' ,'C' from dual
6 union all
7 select 'C','D' from dual
8 union all
9 select 'K','E' from dual
10 )
11 select concat('A->', replace(wm_concat(child1), ',', '->'))
12 from table1
13 start with parent1 = 'A'
14 connect by prior child1 = parent1
15 /

CONCAT('A->',REPLACE(WM_CONCAT
--------------------------------------------------------------------------------
A->B->C->D

SQL>

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SQL code:
10:01:52 tina@PRACTICE> with tb as (
10:01:54 2 select 'A' 主,'B' 元 from dual
10:01:54 3 union all
10:01:54 4 select 'B','C' from dual
10:01:54 5 union all
10:01:54 6 select 'C','D' from dual
10:01:54 7 )
10:01:54 8 select 'A->'||replace(wm_concat(