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Oracle® Database SQL Language Reference
11g Release 1 (11.1)

Part Number B28286-01
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Description of extract_xml.gif follows
Description of the illustration extract_xml.gif


EXTRACT (XML) is similar to the EXISTSNODE function. It applies a VARCHAR2 XPath string and returns an XMLType instance containing an XML fragment. You can specify an absolute XPath_string with an initial slash or a relative XPath_string by omitting the initial slash. If you omit the initial slash, then the context of the relative path defaults to the root node. The optional namespace_string must resolve to a VARCHAR2 value that specifies a default mapping or namespace mapping for prefixes, which Oracle Database uses when evaluating the XPath expression(s).


The following example extracts the value of the /Warehouse/Dock node of the XML path of the warehouse_spec column in the sample table oe.warehouses:

SELECT warehouse_name, EXTRACT(warehouse_spec, '/Warehouse/Docks')
   "Number of Docks"
   FROM warehouses
   WHERE warehouse_spec IS NOT NULL
   ORDER BY warehouse_name, "Number of Docks";

WAREHOUSE_NAME            Number of Docks
------------------------- -------------------------
New Jersey
San Francisco             <Docks>1</Docks>
Seattle, Washington       <Docks>3</Docks>
Southlake, Texas          <Docks>2</Docks>

Compare this example with the example for EXTRACTVALUE, which returns the scalar value of the XML fragment.