ORA-19279

Question

I have written the following SQL to get all the child names:
WITH xml_table AS
(SELECT xmltype('
<root>
<child name="name1">
<grandchild name="name11">
<greatgrandchild name="name111"/>
<greatgrandchild name="name112"/>
</grandchild>
<grandchild name="name12"/>
</child>
<child name="name2">
<grandchild name="name21"/>
<grandchild name="name22"/>
</child>
</root>') object_value FROM dual)
select po.*
from xml_table p,
xmltable('/root' passing p.object_value columns child varchar2(100) path 'child/@name') po;
I understand there are multiple "child" nodes under "root". So how to list them?
I want to store all the "child" names in one table, "child" nodes and their "grandchild" in another table, "grandchild" and "greatgrandchild" in another table. What should be SQLs?

Answer 1

Here's how you can "flatten" the hierarchy, it should give you some pointers to achieve your requirement :
WITH xml_table AS (
SELECT xmltype(
'<root>
<child name="name1">
<grandchild name="name11">
<greatgrandchild name="name111"/>
<greatgrandchild name="name112"/>
</grandchild>
<grandchild name="name12"/>
</child>
<child name="name2">
<grandchild name="name21"/>
<grandchild name="name22"/>
</child>
</root>'
) object_value
FROM dual
SELECT po1.child,
       po2.grandchild,
       po3.greatgrandchild
FROM xml_table p,
     XMLTable(
      '/root/child'
      passing p.object_value
      columns
       child  varchar2(100) path '@name',
       childs xmltype       path '.'
     ) po1,
     XMLTable(
      '/child/grandchild'
      passing po1.childs
      columns
       grandchild  varchar2(100) path '@name',
       grandchilds xmltype       path '.'
     ) (+) po2,
     XMLTable(
      '/grandchild/greatgrandchild'
      passing po2.grandchilds
      columns
       greatgrandchild  varchar2(100) path '@name'
     ) (+) po3
;To deal with missing descendants, note the use of the outer join with the last two XMLTABLEs.