Oracle SQL：如何从分层表中获取XML

Question

id  parent_id  Name         Text
0 ...........  body_text   

1 ..........0  text....... . something

2 ..........0  blank       

3 ..........2  text ........ something

4 ...........  info        

5 ..........4  text ........ something

谁知道如何从上一个分层表获取以下XML格式：

<?xml version "................."?>
<body_text>
<text>something</text>
<blank>
    <text>something</text>
</blank>
</body_text>
<info>
 <text>some</text>
</info>

唯一知道如何做的部分，现在也失效了：

select DBMS_XMLGEN.getXML(DBMS_XMLGEN.newcontextfromhierarchy('SELECT level,
XMLElement(evalname(Name), text))
from my_table t
START WITH id_parent is null
CONNECT BY PRIOR id = parent_id'))
 FROM dual

- user1743671

Answer 1

您提供的查询将会给您期望的结果。只是您有几个语法错误。首先，parent_id 和 id_parent 列名在您的查询中 id 的位置不同。请将它们改为相同。其次，请从 XMLElement(evalname(Name), text)) 中删除最后一个括号 )。

SQL> set long 300

SQL> create table  t1 (id1,  parent_id,  Name1, Text) as(
  2  select 0, null, 'body_text', null        from dual union all
  3  select 1, 0,    'text',      'something' from dual union all
  4  select 2, 0,    'blank',     null        from dual union all
  5  select 3, 2,    'text' ,     'something' from dual union all
  6  select 4, null, 'info',      null        from dual union all
  7  select 5, 4,    'text',     'something'  from dual
  8  );

Table created

SQL> select DBMS_XMLGEN.getXML(DBMS_XMLGEN.newcontextfromhierarchy('SELECT level,
  2     XMLElement(evalname(Name1), text)
  3    from t1 t
  4    start with parent_id is null
  5    connect by prior id1 = parent_id')) xml
  6   from dual
  7  ;

xml
--------------------------------------------------------------------------------
<body_text>
  <text>something</text>
  <blank>
    <text>something</text>
  </blank>
</body_text>
<info>
  <text>something</text>
</info>

SQL>  select '<?xml version="1.0" ?>'
  2     || chr(10)
  3     || DBMS_XMLGEN.getXML(DBMS_XMLGEN.newcontextfromhierarchy('SELECT level,
  4            XMLElement(evalname(Name1), text)
  5          from t1 t
  6          start with parent_id is null
  7          connect by prior id1 = parent_id')) as xml
  8   FROM dual
  9  ;

XML
--------------------------------------------------------------------------------
<?xml version="1.0" ?>
<body_text>
  <text>something</text>
  <blank>
    <text>something</text>
  </blank>
</body_text>
<info>
  <text>something</text>
</info>

- Nick Krasnov