Sql 左外连接,通过根连接
我有Sql 左外连接,通过根连接,sql,oracle10g,connect-by,hierarchical-query,Sql,Oracle10g,Connect By,Hierarchical Query,我有 SELECT CONNECT_BY_ROOT TAXY.IDCATEGORY AS IDBRANCH , TAXY.IDCATEGORY , TAXY.IDPARENTCATEGORY , TAXY.IDCONTENT , TAXY.CATEGORYNAME , LEVEL AS LVL FROM TAXONOMY TAXY CONNECT BY TAXY.IDCATEGORY = PRIOR TAXY.IDPARENTCATEGORY 并希望添加到表CONTE
SELECT
CONNECT_BY_ROOT TAXY.IDCATEGORY AS IDBRANCH
, TAXY.IDCATEGORY
, TAXY.IDPARENTCATEGORY
, TAXY.IDCONTENT
, TAXY.CATEGORYNAME
, LEVEL AS LVL
FROM TAXONOMY TAXY
CONNECT BY TAXY.IDCATEGORY = PRIOR TAXY.IDPARENTCATEGORY
并希望添加到表CONTENT
中的每个条目CONTENTNAME
列中
我试过:
SELECT
CONNECT_BY_ROOT TCT.CONTENTNAME AS ENDNODECONTENTNAME
, TAXY.IDCATEGORY
, TAXY.IDPARENTCATEGORY
, TAXY.IDCONTENT
, TCT.CONTENTNAME
, TAXY.CATEGORYNAME
, LEVEL AS LVL
FROM TAXONOMY TAXY
LEFT OUTER JOIN CONTENT TCT ON TCT.IDCONTENT = TAXY.IDCONTENT
CONNECT BY TAXY.IDCATEGORY = PRIOR TAXY.IDPARENTCATEGORY
期望得到相同的结果,仅使用CONNECT\u BY_ROOT
使用一个额外的列:CONTENTNAME
fromCONTENT
,由IDCONTENT
关联;如果没有相关内容(IDCONTENT
为NULL
),则应为NULL
)
相反,我只获取IDCONTENT
不是NULL
的行。我该怎么做才能得到这些行呢
我也试过:
SELECT
CONNECT_BY_ROOT TAXY.IDCATEGORY AS IDBRANCH
, TAXY.IDCATEGORY
, TAXY.IDPARENTCATEGORY
, TAXY.IDCONTENT
, TCT.CONTENTNAME
, TAXY.CATEGORYNAME
, LEVEL AS LVL
FROM TAXONOMY TAXY
LEFT OUTER JOIN CONTENT TCT ON TCT.IDCONTENT = TAXY.IDCONTENT
CONNECT BY TAXY.IDCATEGORY = PRIOR TAXY.IDPARENTCATEGORY
我也试过了
SELECT
SYS_CONNECT_BY_PATH(TAXY.CATEGORYNAME, ' \ ') AS BREADCRUMBSPATH
, TAXY.IDCATEGORY
, TAXY.IDPARENTCATEGORY
, TAXY.IDCONTENT
, TCT.CONTENTNAME
, TAXY.CATEGORYNAME
, LEVEL AS LVL
FROM TAXONOMY TAXY
LEFT OUTER JOIN CONTENT TCT ON TCT.IDCONTENT = TAXY.IDCONTENT
START WITH TAXY.IDPARENTCATEGORY IS NULL CONNECT BY TAXY.IDPARENTCATEGORY = PRIOR TAXY.IDCATEGORY
但是我得到了相同的结果(只有IDCONTENT
不是NULL
的值)
最奇怪的是,查询昨天在开发数据库上按预期工作,而现在不是。所以我创建了一个小提琴来检查我是否可以重现以前的结果,它工作得很好
是什么导致了这种行为的改变?我仍然不知道发生了什么(仍然不起作用),但这种解决方案似乎在这两种情况下都很有效:
SELECT IDBRANCH, ENDNODEIDCONTENT, IDCATEGORY, IDPARENTCATEGORY, TAXYJ.IDCONTENT, TCT.CONTENTNAME AS ENDNODECONTENTNAME, CATEGORYNAME, LVL
FROM (
SELECT CONNECT_BY_ROOT TAXY.IDCATEGORY AS IDBRANCH
, CONNECT_BY_ROOT TAXY.IDCONTENT AS ENDNODEIDCONTENT
, TAXY.IDCATEGORY
, TAXY.IDPARENTCATEGORY
, TAXY.IDCONTENT
, TAXY.CATEGORYNAME
, LEVEL AS LVL
FROM TAXONOMY TAXY
CONNECT BY TAXY.IDCATEGORY = PRIOR TAXY.IDPARENTCATEGORY
) TAXYJ
LEFT OUTER JOIN CONTENT TCT ON TCT.IDCONTENT = TAXYJ.ENDNODEIDCONTENT