The EXISTSNODE is a condition, unlike
the others, which can be used in the WHERE condition of an
SQL statement. This condition determines whether the
traversal of the XML document or an XML element results in
an available node or not.
This condition produces the literal 1
if the traversing node is found and 0 if it is not found.
The prototype for defining an
EXISTSNODE condition is shown below,
EXISTSNODE(<XML_Document> | <XML_Element>,
<XPath_Expression>)
The below SQL
results in the scalar
value of the node
Genre only if it is present in the parent XML, else it
returns no rows. This logic is handled by the EXISTSNODE
condition as shown below,
SELECT extractvalue(book_details_xml,'/Rack1/Genre')
FROM book_store
WHERE
existsnode(book_details_xml,'/Rack1/Genre')=1;
Result:
Comics
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