HANA Hierarchy 获取节点路径

HANA Hierarchy没有提供sys_connect_by_path的功能，只有通过程获取：

DO
BEGIN
  allhr = 
  		select HIERARCHY_RANK id, HIERARCHY_PARENT_RANK pid, parent_id item, node_id node from (SELECT HIERARCHY_RANK,HIERARCHY_TREE_SIZE,HIERARCHY_PARENT_RANK,HIERARCHY_ROOT_RANK,HIERARCHY_LEVEL,HIERARCHY_IS_CYCLE,HIERARCHY_IS_ORPHAN,PARENT_ID,NODE_ID
			FROM hierarchy (
				SOURCE (SELECT name parent_id,idnrk node_id FROM pcdw.ecc_bom a WHERE WERKS ='L070')
				START WHERE name IN ('7D04CTO1WW','7X18CTO1WW')
			));
  curpath = select id,pid,item,node,item root,item||','||node path from :allhr a where pid=0;
  
  while (select count(*)  from :curpath where id is not null) >0 do
  curpath = select b.id,b.pid,b.item,b.node,a.root,ifnull(a.path||','||b.node,a.path) as path 
  		    from :curpath a left join :allhr b on a.id=b.pid and a.node = b.item;
  
  end while;
  select root,path from :curpath;
END;

找到个新方法：

WITH t_demo AS (
SELECT '1' p,'1.1' c FROM dummy UNION 
SELECT '1' p,'1.2' c FROM dummy UNION 
SELECT '1' p,'1.3' c FROM dummy UNION 
SELECT '1.2' p,'1.2.1' c FROM dummy UNION 
SELECT '2' p,'2.1' c FROM dummy UNION 
SELECT '2' p,'2.2' c FROM dummy UNION 
SELECT '2' p,'2.3' c FROM dummy UNION 
SELECT '2.1' p,'2.1.1' c FROM dummy 
)
, h AS ( SELECT * FROM HIERARCHY (
        SOURCE ( SELECT c node_id, p parent_id FROM t_demo ORDER BY c )
        START WHERE p = '2' ) )
SELECT
    start_id AS node_id,
    STRING_AGG(node_id, '/' ORDER BY hierarchy_rank) AS path
FROM
    HIERARCHY_ANCESTORS(
        SOURCE h 
        START ( SELECT parent_id AS start_id, hierarchy_rank AS start_rank FROM h )
)
GROUP BY
    start_id;